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COMPARISON OF REGULATORY
DESIGN CONCENTRATIONS
AERMOD
vs
ISCST3, CTDMPLUS, ISC-PRIME
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EPA-454/R-03-002
June 2003
COMPARISON OF REGULATORY
DESIGN CONCENTRATIONS
AERMOD
vs
ISCST3, CTDMPLUS, ISC-PRIME
Staff Report
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emissions Monitoring and Analysis Division
Research Triangle Park, North Carolina
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Disclaimer
This report has been reviewed by the Office of Air Qualtiy Planning and Standards, U.S.
Environmental Protection Agency, and has been approved for publication. Mention of trade
names or commercial products does not constitute endorsement or recommendation for use.
Acknowledgments
The Agency wishes to acknowledge AERMIC (the American Meteorological
Society/Environmental Protection Agency Regulatory Model Improvement Committee),
members of which have given a considerable amount of time, energy and dedication over the last
10 years to develop the AERMOD air dispersion modeling system:
W.D. Peters, U.S. Environmental Protection Agency, OAQPS, EMAD,AQMG
A. Venkatram, College of Engineering, University of California at Riverside
J. C. Weil, Cooperative Institute for Research in Environmental Sciences,
University of Colorado
R. B. Wilson, U.S. Environmental Protection Agency, Region X
R. J. Paine, ENSR Corporation
S.G. Perry1, Atmospheric Sciences Modeling Division,
Air Resources Laboratory, EPA/ NOAA
R. F. Lee, Consultant, Meteorologist
A. J. Cimorelli, U.S. Environmental Protection Agency, Region III
In addition, Mr. Roger Erode of MACTEC Federal Programs, Inc. (formerly known as Pacific
Environmental Services Inc) has provided considerable talent and support to the AERMOD
project and has conducted many analyses over the last several years to test and develop this new
air dispersion model.
^n assignment to the Atmospheric Research and Exposure Assessment Laboratory, U.S.
Environmental Protection Agency.
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TABLE OF CONTENTS
1. INTRODUCTION 4
2. METEOROLOGICAL DATA BASES 10
3. MODEL OPTIONS AND SOURCE DEFINITIONS 14
4. MODELING RESULTS 21
5. DISCUSSION OF RESULTS 29
6. GENERAL CONCLUSIONS 36
7. COMPUTER RUN TIMES 37
APPENDIX A
SIDE BY SIDE COMPARISON OF MODEL FEATURES:
AERMOD VS ISCST3 38
APPENDIX B
FIGURES FOR DESCRIBING COMPLEX TERRAIN 44
APPENDIX C
LOCATION OF SOURCE AND RECEPTORS FOR THE
COMPLEX TERRAIN ANALYSIS 51
APPENDIX D
FLAT AND SIMPLE TERRAIN MODELING RESULTS 67
APPENDIX E
COMPLEX TERRAIN MODELING RESULTS 80
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1. INTRODUCTION
1.1 Background information.
This report is a final version of an earlier consequence analysis2, which was released to
support the proposal of AERMOD (the American Meteorological Society/Environmental
Protection Agency Regulatory Model Improvement Committee's Dispersion Model, version
99351) in a Federal Register notice3 on April 21, 2000. At that time, the EPA also proposed an
additional model, ISC-PRIME ( Industrial Source Complex -Short Term Model[Version 3] -
Plume Rise Model Enhancements), designed to be used in cases where building downwash was
significant; AERMOD was to be used for air pollution source scenarios where downwash was not
an issue. To support the ISC-PRIME proposal, there was a separate but similar building-
downwash-consequence analysis completed which compared ISC-PRIME to ISCST34 (Industrial
Source Complex -Short Term Model—Version 3). Responding to the overwhelming reaction from
the commenters on the proposal, the Agency decided to incorporate PRIME algorithms into
AERMOD and thereby eliminate the use of the ISC-PRIME model. The final results in this report
consider both downwash and non-downwash source scenarios since AERMOD now provides the
state of the science for modeling both types of source scenarios. Thus, this report is designed to
supercede the two earlier consequence analyses.
This analysis is based on the lastest version of AERMOD, version 022225, which includes
the PRIME algorithms and the proposed version of AERMOD (99351). The ISC-PRIME results
are based on version 99020; the ISCST3 results are based on version 96113 (for the downwash
analysis) and version 97363 (for the point, area and volume sources) which are the same versions
of the models used in the earlier consequence analyses.
The introduction includes the following additional sections: a description and purpose of a
consequence analysis; a description of the 3 components to this study; and, a brief description of
the air dispersion models of interest - AERMOD (including a list of AERMOD changes since the
proposal), ISCST3, ISC-PRIME, and, CTDMPLUS (the Complex Terrain Dispersion Model-
Plus)
1.2 What is a consequence analysis?
The purpose of this report, often called a consequence analysis, is to give the user
community a sense of how regulatory design concentrations from a new air dispersion model
compare to those from an established model via a series of "representative" examples. After the
release of a new model for regulatory applications, the user community will want to know: "What
does this mean to my modeling projects?". This analysis is designed to answer that question by
2Peters,W.D. et al, "Comparison of Regulatory Design Coi
draft document, April 1999, available on the EPA website:
'Federal Register notice, 65FR21506, April 21, 2000.
Concentrations: AERMOD versus ISCST3 and CTDMPlus",
: www.epa.gov/scramOO 1.
4Paine, R.J. and Lew, F., "Consequence Analysis for Adoption of PRIME: an Advanced Building Downwash Model",
August 24, 1998, available on the EPA website: www.epa.gov/scramOO 1.
5Available on the EPA website: www.epa.gov/scramOO 1.
4
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showing the effects of the new model as compared to the existing regulatory model which it
replaces. For this study, the new model is AERMOD with the PRIME algorithms. The existing
regulatory models used in this report are ISCST3, ISC-PRIME, and CTDMPLUS. This
consequence analysis does not substitute for detailed comparative evaluations or sensitivity
analyses, but rather, provides to the modeler some simple comparisons of regulatory design
concentration estimates from these air quality models for an extensive number of typical source
scenarios.
1.3 The three components of this study.
There are three parts to this study: the flat and simple terrain component; the building
downwash component; and, the complex terrain component. The building downwash component
has been added to the original report since AERMOD now contains the PRIME building
downwash feature and will be used for sources near buildings. All of the study components use
source scenarios and meteorological data sets which remain unchanged from the earlier
consequence analyses.
The flat and simple terrain consequence analysis is based on comparative runs made using
a composite of standard data sets. These data sets include a range of point sources with varying
stack parameters, area and volume sources, and two point sources in simple terrain6. All source
scenarios are evaluated with two meteorological data sets representing different climatic regimes
in the U.S. For building downwash, a series of point sources with varying stack heights and
different building configurations are included in the data sets. Only one of the meteorological
data sets used in the previous description is used in this part of the analysis. For the complex
terrain, the study includes a number of stack heights, buoyancy regimes, distances from source to
hill, and hill types along with its own meteorological data base (one site).
After applying the model to all of the above source scenarios, the consequence analysis is
summarized by tabulating the important regulatory (design) concentrations for the new model
against those predicted by the existing regulatory models. Often, the concentrations of regulatory
interest are the high and the high-second-highest concentrations for 1-hour, 3-hour, 24-hour, and
annual averages, and they are used in this study. The choice of averaging times is based on the
earlier consequence analyses, although this choice is not consistent across all three components of
this study.
1.4 A Brief Description of AERMOD7
A committee, AERMIC (the American Meteorological Society/Environmental Protection
Agency Regulatory Model Improvement Committee), was formed to introduce state-of-the-art
modeling concepts into the EPA's local-scale air quality models. AERMIC's focus was on a new
platform for regulatory steady-state plume modeling; this platform would include air dispersion
6 Simple terrain includes receptors with elevations below the top of the stack and at elevations above or below the stack
base. Intermediate terrain includes receptors with elevations above stack top and below the plume centerline.
Complex terrain includes receptors with elevations above the top of the stack.
'User's Guide for the AMS/EPA Regulatory Model - AERMOD, US EPA, Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, Report No EPA-454/B-03-001, July 2003. Available on the EPA
website: www.epa.gov/scramOO 1.
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fundamentally based on planetary boundary layer turbulence structure, scaling and concepts.
AERMOD is designed to treat both surface and elevated sources in simple and complex terrain.
Special features of AERMOD include its ability to treat the vertical inhomogeneity of the
planetary boundary layer, special treatment of surface releases, irregularly-shaped area sources, a
three-plume model for the convective boundary layer, and limitation of vertical mixing in the
stable boundary layer. A treatment of dispersion in the presence of intermediate and complex
terrain is used that improves on that treatment currently in use in ISCST3 and other models, yet
without the complexity of a model such as CTDMPLUS.
AERMOD incorporates, with a new simple approach, current concepts about flow and
dispersion in complex terrain. Where appropriate, the plume is modeled as either impacting and/or
following the terrain. This approach is designed to be physically realistic and simple to implement
while avoiding the need to distinguish among simple, intermediate and complex terrain, as is
required by present regulatory models. As a result, AERMOD removes the need for defining
complex terrain regimes; all terrain is handled in a consistent and continuous manner that is
simple while still considering the dividing streamline concept in stably-stratified conditions.
AERMOD is actually a modeling system with three separate components: AERMOD
(AERMIC Dispersion Model), AERMAP (AERMOD Terrain Preprocessor), and AERMET
(AERMOD Meteorological Preprocessor).
AERMET is the meteorological preprocessor for AERMOD. Input data can come from
hourly cloud cover observations, surface meteorological observations and twice-a-day upper air
soundings. Output includes surface meteorological observations and parameters and vertical
profiles of several atmosheric parameters.
AERMAP is a terrain preprocessor designed to simplify and standardize the input of terrain
data for AERMOD. Input data include receptor terrain elevation data. The terrain data may be in
the form of digital terrain data that is available from the U.S. Geological Survey. For each
receptor, the output includes a location and height scale, which is an elevation used for the
computation of air flow around hills.
Additional information about AERMOD can be found in other documents. The model
evaluation paper8 compares both AERMOD (proposed and current versions), CTDMPLUS,
ISCSTS's and ISC-PRIME's model predictions against measured ambient concentrations. The
Model Formulation Document9 provides a detailed explanation of the science behind the model.
8 USEPA, "AERMOD: Latest features and Evaluation Results." Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711, EPA Report No. EPA-454/R-03-003. July 2003. Available on the EPA website:
www.epa. gov/scramOO 1.
9 USEPA, " AERMOD: Description of Model Formulation (Version 02222) ", Office of Air Quality Planning and
Standards, Research Triangle Park, NC 27711, EPA Report No. EPA-454/R-03-004, October 2002. Available on the
EPA website: www.epa.gov/scram001.
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The AERMOD, AERMET and AERMAP User's Guides7-10-11 inform the user community about
the various options and features of the model and its preprocessors.
1.5 Changes made to AERMOD since the proposal
A summary of the changes made to the AERMOD in response to comments include the
following:
* adding the PRIME algorithms to the model (response to public comments);
* modifying the complex terrain algorithms to make AERMOD less sensitive to the
selection of the domain of the study area (response to public comments);
* modifying the urban dispersion for low-level emission sources, such as area sources, to
produce a more realistic urban dispersion and, as a part of this change, changing the
minimum layer depth used to calculate the effective dispersion parameters for all
dispersion settings (scientific formulation correction which was requested by beta testers);
and making an adjustment to the friction velocity and the Monin-Obukhov length for urban
stable cases (improved scientific formulation);
* upgrading AERMOD to include all the newest features that exist in the latest version of
ISC such as FORTRAN 90 compliance and allocatable arrays, EVENTS processing and
the TOXICS option (response to public comments).
In doing the follow-up quality control checking of the model and the source code, the need
for additional changes were identified and the following changes have been made:
* adding meander to: 1) the stable and unstable urban and 2) the rural unstable dispersion
settings (only the rural, stable dispersion setting considered meander in the earlier version of
AERMOD - this change provides a consistent treatment of air dispersion in all dispersion
settings);
* making some changes to the basic meander algorithms (improved scientific formulation);
* making a correction to avoid elevated concentrations for terrain below stack base from the
virtual image source (response to public comments about spurious results in complex
terrain); and,
* repairing miscellaneous coding errors.
A more detailed list of corrections are given in the model evaluation paper8.
1.6 Overview of ISCST312.
10USEPA, "User's Guide for the AERMOD Meteorological Preprocessor (AERMET)", US EPA, Office of Air
Quality Planning and Standards, Research Triangle Park, NC 27711, EPA Report No EPA-454/B-03-002, July 2003.
Available on the EPA website: www.epa.gov/scramOO 1.
"USEPA, "User's Guide for the AERMOD Terrain Preprocessor (AERMAP), US EPA, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, EPA Report No EPA-454/B-03-003, August 2002.
Available on the EPA website: www.epa.gov/scramOO 1.
12USEPA,"User's Guide for the Industrial Source Complex (ISC3) Dispersion Models", Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, Report No. EPA-454/B-95-003a, September 1995.
Available on the EPA website: www.epa.gov/scramOO 1.
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ISCST3 is especially designed to support the EPA's regulatory modeling programs. This
model is a steady-state Gaussian dispersion model with a number of options available to the user.
These options include the use of stack-tip downwash, buoyancy-induced dispersion, final plume
rise (except for sources with building downwash), a routine for processing averages when calm
winds occur, and default values for wind profile exponents and for the vertical potential
temperature gradients. The Short Term model also incorporates COMPLEXl screening model
dispersion algorithms for receptors in complex terrain. The user may select either rural or urban
dispersion parameters, depending on the characteristics of the source location. A more detailed
side-by-side explanation and comparison of features between ISCST3 and AERMOD is given in
Appendix A.
1.7 Overview of PRIME.
PRIME was developed by the Electric Power Research Institute to provide new and
improved plume rise and building downwash algorithms. The PRIME set of algorithms was
incorporated into ISCST3 and the new model was called ISC-PRIME. The improved algorithms
provided the following new features:
. consideration of the location of the stack in relationship to the building;
. consideration of the streamline deflection over the building;
. inclusion of plume rise affected by the velocity deficit in the wake or vertical wind speed
shear;
. a linkage between plume material captured by the near wake and far wake concentrations;
. elimination of discontinuities at the interface between the two downwash algorithms;
. provision of wind direction effects for squat buildings;
. elimination of the large concentrations predicted by ISCST3 during light wind speed,
stable conditions that are not supported by observations.
A further, more detailed, description of the model13 and the evaluation results 14are available.
1.8 A Brief Description of CTDMPLUS15
CTDMPLUS is a refined Gaussian plume dispersion model designed to estimate hourly
concentrations of plume material from elevated point sources at receptors on or near isolated terrain
features. This model can assess stable and neutral atmospheric conditions as well as daytime,
unstable conditions. Its use of meteorological data and terrain information is different from other
regulatory models in that considerable detail for both types of input data is required and is supplied
by preprocessors specifically designed for CTDMPLUS.
13 L.L. Schulman, D.G. Strimaitis, IS. Scire, "Development and Evaluation of the PRIME Plume Rise and Building
Downwash Model", Jounrnal of Air and Waste Management Association, 50: 378-390, March 2000.
14 R. J. Paine, F. Lew, "Results of of the Independent Evaluation of ISCST3 and ISC-PRIME", Electric Research
Institute, EPRI TR-2460026, November 1997. Available at www.epa.gov/scramOO 1.
15 User's Guide to the Complex Terrain Dispersion Model Plus Algorithm for Unstable Situations, US EPA,
Atmospheric Research and Exposure Assessment Laboratory, Research Triangle Park, NC 27711, Report No.
EPA/600/8-89/041, March 1989. Available on the EPA website: www.epa.gov/scram001.
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In modeling stable to neutral conditions, a central feature of CTDMPLUS is its use of a
critical dividing-streamline height to separate the flow in the vicinity of a hill into two separate
layers. Flow in the upper layer has sufficient kinetic energy to pass over the top of the hill, while
the streamlines in the lower layer are constrained to flow in a horizontal plane around the hill. In
modeling unstable or convective conditions, the model relies on a probability density function
(PDF) description of the vertical velocities to estimate the vertical distribution of pollutants.
Hourly profiles of wind and temperature measurements are used by CTDMPLUS to
compute plume rise, plume penetration, convective scaling parameters. In stable/neutral conditions,
the profiles of turbulence data are used to compute dispersion parameter values at plume height.
The model calculates on an hourly basis how the plume trajectory is deformed by each hill.
The computed concentration at each receptor is then derived from the receptor position on the hill
and the resultant plume position and shape.
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2. METEOROLOGICAL DATA BASES
2.1 Flat and Simple Terrain
One year of hourly data for two sites were retrieved and processed. The two sites selected
for this study are Pittsburgh, PA (WBAN [Weather Bureau-Air Force-Navy] station No. 94823),
representative of an urban eastern site; and Oklahoma City, OK (WBAN station No. 13967),
representative of a southwestern plains site. The 1964 data are used at the Pittsburgh site and 1984
data are used at the Oklahoma City site. ISCST3 meteorological data were preprocessed by
PCRAMMET and AERMOD meteorological data were preprocessed by AERMET.
2.1.1 AERMET Overview. AERMET '"provides a general purpose meteorological
preprocessor for organizing available meteorological data into a format suitable for use by
AERMOD. National Weather Service (NWS) hourly surface observations and twice-daily upper
air soundings, plus site-specific data from a meteorological measurement program can be processed
in AERMET. There are three stages to processing the data. The first stage extracts meteorological
data from archive data files and processes the data through various quality assessment checks. The
second stage merges all data available for 24-hour periods (NWS and site-specific data) and stores
these data together in a single file. The third stage reads the merged meteorological data and
estimates the necessary parameters for use by AERMOD. Two files are written for AERMOD: 1) a
file of hourly boundary layer parameter estimates; and, 2) a file of multiple-level observations
(profiles) of wind speed and direction, temperature, and standard deviation of the fluctuating
horizontal and vertical components of the wind.
Input data used in this part of the study include: 1) hourly specification of wind speed; 2)
hourly specification of wind direction; 3) hourly ambient temperature; 4) hourly solar radiation16;
5) hourly cloud cover values; 6) a quantification of surface characteristics (surface roughness,
albedo, Bowen ratio); and 7) twice-daily upper air soundings17. Output includes hourly values for
mixing heights and Monin-Obukhov lengths, surface friction velocity, convective velocity scale,
and profiles of wind speed and direction, temperature and turbulence. Table 2-1 lists the albedo,
Bowen ratio, and surface roughness that are assumed for this analysis. Table 2-1 lists only the
rural settings for the meteorological data. The urban analysis is accomplished by setting the urban
mode and urban source option in AERMOD and using the rural meteorological data for the model
inputs.
16Solar and Meteorological Surface Observation Network 1961-1990, Version 1.0, US Department of Commerce,
National Climatic Data Center, Asheville, NC / US Department of Energy, National Renewable Energy Laboratory,
Golden CO, September 1993.
"Radiosonde Data of North America 1946-1992, Version 1.0, Forecast Systems Laboratory, Boulder, CO and
National Climatic Data Center, Asheville, NC, August 1993.
10
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Table 2-1. Albedo, Bowen Ratio, and Surface Roughness length assumed for AERMET
preprocessor.
Site
Pittsburgh
Oklahoma City
Option
Rural
Rural
Albedo
0.25
0.25
Bowen
Ratio
0.75
0.75
Surface roughness
(meters)
0.15
0.15
2.1.2 PCRAMMET Overview. The PCRAMMET 18model requires the twice-daily
mixing heights and NWS surface observations. Prior to being made available, the data were
checked for blank fields (missing data) and filled by accepted procedures. A modification was
made to the data sets by setting the minimum mixing heights to 10 meters. This change was made
to avoid spuriously high or low concentrations for the short stacks. Only the meteorological data
used for the ISCST3 analysis was affected.
For ISCST3, the minimum input data requirements to the PCRAMMET are the twice-daily
mixing heights and hourly surface observations of wind speed, wind direction, dry bulb
temperature, opaque cloud cover and ceiling height. The operations performed by the
PCRAMMET include: 1) calculation of hourly values for atmospheric stability from
meteorological surface observations; and, 2) interpolation of twice-daily-mixing heights to hourly
values. A brief description of the meteorological data for the two sites is given in Table 2-2.
Table 2-2. Missing soundings and calm wind conditions by site and year.
Site Year
Pittsburgh 1964
Oklahoma City 1984
Anemometer
height (feet)
20
20
Hours/
year
8784
8784
Missing Soundings
0000 GMT19 1200 GMT
0 0
0 0
Calm wind
conditions
858
181
18 PCRAMMET User's Guide, US EPA, Office of Air Quality Planning and Standards, RTF, NC 27711, EPA-454/B-
96-001, October 1996. Available fromEPA's world-wide-web site atwww.epa.gov/scram001.
19 GMT = Greenwich Mean Time
11
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2.2 Building Downwash.
Only the meteorological data from Pittsburgh (1964), as described in the preceding section,
is used in the building downwash scenarios. No modifications were made to the data because there
are no short stacks, (i.e. less than 20 meters) in this part of the analysis.
2.3 Complex Terrain.
The meteorological data base used in the complex terrain portion of this study is taken from
a project where site-specific data were collected20. A 100-m tower, instrumented at 10, 50, and 100
meters and sodar equipment were used to gather the meteorological data. The sodar data was
collected at 50-meter intervals, and the 150 - 400 meter sodar data were used with the tower data to
construct the meteorological profiles. The use of sodar turbulence data is limited to vertical
turbulence values only. All of the tower and sodar levels are used in AERMOD and CTDMPLUS
runs. Only the 100-m tower data (wind speed and wind direction) are used in ISCST3 runs (see
Figure 2-1 for the 100 meter wind rose). The atmospheric turbulence and dispersion for ISCST3
are addressed by applying atmospheric stability classifications which are estimated by the solar
radiation/delta-T (SRDT) stability scheme21.
To confine the differences between CTDMPLUS and AERMOD to differences in the
dispersion algorithms, the METPRO22 output used for CTDMPLUS (including the boundary layer
parameters) is reformatted in a mode compatible with AERMOD meteorological data requirements.
However, the predicted concentrations are not sensitive to these boundary layer values because
profiled meteorological data are available at several levels straddling the stack release heights.
20 The data came from an unnamed source.
21 "An Evaluation of A Solar Radiation/Delta-T Method for EstimatingPasquill-Gifford (P-G) Stability Categories",
EPA-454/R-93-055, October 1993.
22 "User's Guide to the CTDM Meteorological Preprocessor Program", EPA-600/8-88-004, 1988. Available on the
EPA website: www.epa.gov/scram001.
12
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Wind Rose for 100-m Tower Winds
W —
11.0
1.8 3.3 5.4 8.f
WIND SPEED CLASS BOUNDARIES
(METERS/SECOND)
NOTES:
DIAGRAM OF THE FREQUENCY OF
OCCURRENCE FOR EACH WIND DIRECTION.
WIND DIRECTION IS THE DIRECTION
FROM WHICH THE WIND IS BLOWING.
EXAMPLE - WIND IS BLOWING FROM THE
NORTH 3.7 PERCENT OF THE TIME.
WINDROSE
2-1.
13
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3. MODEL OPTIONS AND SOURCE DEFINITIONS
3.1 Modeling Options for Flat, Simple and Complex Terrain.
The regulatory dispersion model used in this study for the flat and simple terrain is the
ISCST3 model. The model was run in the "regulatory mode" which uses the option settings as
described in Table 3-1. Table 3-1 also shows the parallel settings or options used for AERMOD
setup.
Table 3-1. Model Options Used in Consequence Analysis.
ISCST3
* Use stack tip downwash
* Use buoyancy -induced dispersion
* Do not use gradual plume rise (gradual plume
rise is used in complex terrain)
* Use the calms-processing routines
* Use default wind profile exponents
* Use default vertical potential temperature
gradients
AERMOD
* Use stack tip downwash
* Use buoyancy-induced dispersion (not
an option)
* Use gradual plume rise (not an option)
* Use the calms-processing routines(not an
option)
* Calculate wind profiles (not an option)
* Calculate vertical potential temperature
gradients (not an option)
The results reported in these 2 components of the study are the high and the highest second-
high concentrations averaged over 1-hr, 3-hr and 24-hr short term averages and the high annual
average.
3.2 Source Characteristics for Flat, Simple Terrain
Ten source types are processed for the flat terrain part of this study: seven point sources,
one area source and two volume sources. Source characteristics for each source type are presented
in Table 3-2. The very buoyant 35 meter stack source and the 200 meter stack source in Table 3-2
are used in the simple terrain part of this study. All these sources are evaluated using: 1) both the
rural and urban settings; and 2) both sets of meteorological data. Thus, there are 48 scenarios
[(10 flat terrain sources + 2 simple terrain sources) x 2 land use settings (rural, urban) x 2
meteorological sites] and 7 different maximum concentration values for a total of 336 cases .
14
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Table 3-2. Source characteristics for flat and simple terrain.
Point sources
Stack height
(m)
5
10
20
35
(moderately
buoyant)
35 (very
buoyant)23*
100
200*
X,Y location & base
elevation (m)
0,0,0
0,0,0
0,0,0
0,0,0
0,0,0
0,0,0
0,0,0
Emission rate
(g^1)
100
100
100
100
100
100
100
Exit velocity
(ms-1)
0
0
0
11.7
11.7
18.8
26.5
Stack diameter
(m)
2.4
2.4
2.4
2.4
2.4
4.6
5.6
Temperature
(K)
Ambient
Ambient
Ambient
293
432
416
425
Area source
Area (m2)
1,000,000
Length of side (m)
1000
Emission rate Height of emission
(gs^rn2) release (m)
0.0001 0.0
Volume sources
Emission rate
(gs'1)
100
100
Height of emision
release (m)
10
35
Length of side divided
by 4.3 (m)
14.
14.
Vertical dimension
divided by 4. 3 (m)
16.
16.
23* These sources are also used for the simple terrain part of the consequence analysis.
15
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3.3 Source Characteristics for Complex Terrain.
The complex terrain analysis examines a combination of four hills, two stack heights, two
buoyancies, and two source-hill distances. The four hills are: 1) Piedmont, a hill near Keyser, WV;
2) Montour Ridge - Crosswind, near Sunbury, PA; 3) Montour Ridge - Alongwind; and 4)
Cinder Cone Butte, located near Boise, ID. Except for "Montour Crosswind", the sources are
located to the west of the hill centers, at distances of about 1 kilometer for the "close-in" case and
about 10 kilometers for the "far-out" case (See Appendix B for the figures describing the hills).
For "Montour Crosswind", the sources are located to the north of the east-west oriented ridge. The
meteorological data base used in this study features a high percentage of winds from the northwest
quadrant (see Figure 2-1). Therefore, the modeling results reflect a large number of cases of plume
transport from the hypothetical sources to these hills. The source parameters for the complex
terrain analysis are provided in Table 3-3. Although there are 32 possible combinations of
hill/source/source-hill distances ( 4 hills x 2 stack heights x 2 buoyancies x 2 source hill distances),
the plume never significantly impacts the Cinder Cone Butte hill in 4 of the cases and are not
included in the analysis. Thus, the results are reported for a total of 28 complex terrain cases.
3.4 Source Characteristics for Building Downwash.
A series of hypothetical scenarios involving single point sources and rectangularly shaped
buildings were chosen in an earlier work and these configurations are retained for this study.
ISCST3, ISC-PRIME and AERMOD are applied to each scenario. The test cases include the
following situations:
* a stack adjacent to a building structure, and also four building heights away from the northeast
corner of the building;
* stack height to building height ratios of 1.0 and 2.0;
* squat, supersquat, and tall building shapes; and,
* urban and rural settings.
A no-building set of cases is also used for "control" runs. Not counting the no-building cases,
there are 20 source/building scenarios and three averaging times to provide a total of 60 cases in
this component of the study. The selection of this set of source configurations and averaging times
matches that of the earlier consequence analysis.
The stack parameters are listed in Table 3.4.
One year of meteorological data (Pittsburgh, 1964) is employed in this analysis. The results
for the highest second-highest 3-hour and 24-hour concentrations, as well as the highest annual
concentration are tabulated for each run. The analysis also includes the model predictions for the
highest 1 hour cavity concentration.
16
-------
Table 3-3. Complex Terrain Source Configurations.
Stack height -
Buoyancy
Low/Low
Low/High
High/Low
High/High
Emission rate
(g/s)
1.0
1.0
1.0
1.0
Stack Height
(m)
30.
30.
150.
150.
Stack Gas
Temperature
(K)
400.
500.
400.
500.
Exit
Velocity
(m/s)
10.
30.
10.
30.
Stack
Diameter
(m)
2.0
6.
2.0
6.
Table 3-4. Source characteristics for building downwash analysis - point sources.
Stack height (m)
35
100
Emission rate
(gs'1)
100
100
Exit velocity
(ms-1)
11.7
18.8
Stack diameter
(m)
2.4
4.6
Temperature
(K)
432
416
3.5 Receptor Configuration for Flat and Simple Terrain
A gridded polar array of receptors is used in the flat terrain portion of the analysis. For the
point sources, there are 36 radials (beginning at 10 degrees from north and spaced every 10
degrees). The distance of the concentric rings are: 125m, 250m, 400m, 800m, 2000m, 4000m,
8000m, and 16000m. The volume and the area source polar grid is also set up for 10 degree radials
but uses concentric ring distances of 125m, 250m, 400m, 800m, and 2000m.
A gridded polar array of receptors is used for the point sources in simple terrain settings.
There are 36 radials (beginning at 10 degrees from north and spaced every 10 degrees). The
distance of the concentric rings were: 800m, 2000m, 4000m, 7000m, and 15000m. The
elevations for the receptors are plotted (with isopleths) in Figures 3-1 (35 meter stack) and 3-2
(200 meter stack).
17
-------
3.6 Receptor Configuration for Building Downwash.
A cartesian receptor grid extending out to 10 kilometers is used in the building downwash
analysis. The receptor density varies, with 50-m spacing for the first 500 meters, 100 m spacing out
to 1000 m, 200 m spacing out to 2000 m and 1000 m spacing out to 10000 m. This spacing
matches that used in the original ISC-PRIME consequence analysis.
3.7 The Complex Terrain Receptor Locations.
The Figures in Appendix B show the contours of the hills used in the analysis. AERMOD,
ISCST3, and CTDMPLUS are run with the full year of data described above for 28 combinations of
sources, and source-hill distances (1 and 10 kilometers). The CCB andMontour
longwind/crosswind setting includes a total of 140 receptors; the Piedmont Hill setting uses a total
of 144 receptors; and, the Cinder Cone Butte setting uses 140 receptors. Appendix C contains the
input files used to run AERMOD and provides the location and elevations of all the receptor
locations for all runs. In all cases, each model estimates concentrations on single hills downwind
from the source.
18
-------
Figure 3-1
Elevation in Feet Around the 35 Meter Stack
15000
10000
5000
CD
-5000
-10000
-15000
§
-15000 -10000 -5000 0 5000 10000 15000
Meters (m)
Note: 25 ft. contours
Stack base = 797 feet, stack top = 911 feet
19
-------
Figure 3-2
Elevation in Feet Around the 200 Meter Stack
15000
CO
10000
5000
0
-5000
-10000
-15000
r//
8
-15000 -10000 -5000 0 5000 10000
Meters (m)
Note: 100 ft. contours
Stack base = 797 feet, stack top = 1453 feet.
15000
20
-------
4. MODELING RESULTS
The results from the three components of the study are given in this section. The three
components are for the flat and simple terrain, the building downwash and the complex terrain
scenarios. The results compare the new (AERMOD version 02222) versus the old model's (ISCST3
or ISC-PRIME) predicted maximum concentrations. The relationship between the current version
of AERMOD versus the old model is the focal point of this study. Generally, the modeling
community is not concerned about the magnitude of the concentration predictions, but is interested
in those situations where the new model predicts higher or lower concentrations than the old model.
Thus, the parameter of choice to present the consequences of the new model is the concentration
ratio. The concentration ratio can be calculated by dividing the current version of AERMOD's
maximum predicted concentration by the old model's corresponding maximum concentration. The
concentration ratio parameter is convenient because a ratio greater than 1 occurs when the new
model predicts maximum concentrations higher than the old model and, conversely, concentration
ratios less than 1 occur when the new model predicts lower maximum concentrations.
As additional information for those who are interested in the model changes since the
proposal, the results include concentration ratios which are based on the earlier consequence
analyses2. That is, the concentration ratios between the current version of the AERMOD versus the
proposed version of AERMOD (version 99351) are provided. Often, this second set of
concentration ratios is redundant, but they directly help readers who are familiar with the original
consequence analysis and who want to study the changes to the consequences subsequent to the
Federal Register proposal3.
4.1 The Flat and Simple Terrain Results.
The results for the flat and simple terrain part of this study are found in Appendix D. The
high and the highest second high (H2H) concentrations for the 1, 3, 24 hour and annual averaging
times are provided for the ISCST3 model (column 2) and, in parallel, the concentration ratios are
provided for the proposed and the current version of AERMOD (columns 3 and 4). The third
column reproduces information presented in the earlier consequence analysis, that is, the ratio of
maximum concentrations comparing the proposed version of AERMOD to ISCST3. The last
column of numbers presents the ratio of the air quality concentrations as predicted by the current
versus the proposed version of AERMOD. Although redundant, this last column helps the reader
to quickly determine the changes in the consequence analysis since the April 1999 report. Each
modeling scenario is defined by a code and the code key is provided at the bottom of each page for
convenience.
Because of the amount of data and complexity of the tables in Appendix D, a series of tables
are presented to summarize the statistics of the relationship between the predicted concentrations
from AERMOD and ISCST3. Tables 4-1, 4-2 and 4-3 have identical structures. There are 4
columns of numbers providing a distribution of concentration ratios. The second column provides a
distribution, an average and the maximum and minimum value of the concentration ratios, for the
proposed version of AERMOD versus ISCST3, as reported in Appendix D. Again, this is a
21
-------
reference point back to the earlier consequence analysis. The third column shows the new
concentration ratios based on the current version of AERMOD (02222) and ISCST3. The last
column is redundant but directly supplies information about the magnitude of the changes between
the earlier and the current version of the new air dispersion model since those ratios compare the
new version of AERMOD to the proposed version of AERMOD. Table 4-1 provides the results for
all the modeling scenarios, while Tables 4-2 and Tables 4-3 break out the results by the rural and
urban settings.
For example, to further explain the summary tables, refer to the third column in Table 4-1.
According to the number in the second row, there are 5 cases where the current version of
AERMOD predicts a maximum concentration that is a factor of 3 greater than ISCST's prediction.
The third row, column 3 indicates that there are 25 cases where AERMOD's predictions are a factor
of 2 greater than ISCST3's. The fifth row indicates the total number of cases (336) in this
component of the study. The fourth row and the sixth row values are the most significant. These
entries provide the number of cases where the AERMOD (version 02222) maximum concentrations
are higher than ISCST3's (116) or lower than ISCST3's maximum concentrations (220). In the
seventh row, there are 46 cases where AERMOD concentrations are less than /^ of the ISCST3 's
maximum concentrations. The average concentration ratio in row 10, the highest ratio in row 11
and the lowest ratio are based on all 336 cases.
Table 4-1. Summary statistics based on the ratio of AERMOD predicted
concentration to ISCST3 predicted concentrations for flat and simple terrain
(see Appendix D) over all averaging times and all source types and both rural
and urban settings.
no. of ratios > 4
no. of ratios > 3
no. of ratios > 2
no. of ratios > 1
Total No.
no. of ratios < 1 .0
no. of ratios < 0.5
no. of ratios <0.33
no. of ratios < 0.25
average
high
low
99351AER/
ISC
1
12
43
157
336
179
44
11
2
1.14
4.25
0.22
02222AER/
ISC
0
5
25
116
336
220
46
14
3
0.96
3.82
0.20
02222AER/
99351AER
0
0
0
82
336
254
24
7
1
0.90
1.73
0.22
22
-------
Table 4-2. Summary statistics based on the ratio of AERMOD predicted concentration to ISCST3
predicted concentrations for flat and simple terrain (see Appendix D) overall averaging times and all
source types - FOR THE RURAL SETTING ONLY.
RURAL RESULTS
99351AER/ 02222AER/
ISC3 ISC3
number of ratios >4
>3
>2
>1
total
<1.0
<0.5
<0.33
<0.25
max
min
average
0
8
27
91
168
77
16
0
0
3.89
0.35
1.25
0
5
25
85
168
83
6
0
0
3.83
0.41
1.21
02222AER/
99351AER
0
0
0
48
168
120
0
0
0
1.73
0.73
1.00
Table 4-3. Summary statistics based on the ratio of AERMOD predicted concentration to ISCST3
predicted concentrations for flat and simple terrain (see Appendix D) overall averaging times and all
source types - FOR THE URBAN SETTING ONLY.
URBAN RESULTS
99351AER/ 02222AER/
ISC3 ISC3
number of ratios >4
>3
>2
>1
total
<1.0
<0.5
<0.33
<0.25
max
min
average
1
4
16
66
168
102
28
11
2
4.25
0.22
1.02
0
0
0
31
168
137
40
14
3
1.49
0.20
0.71
02222AER/
99351AER
0
0
0
34
168
134
24
7
1
1.61
0.22
0.80
23
-------
4.2 The Building Downwash Results.
As mentioned in the introduction, this section was not in the April 1999 AERMOD
consequence analysis since AERMOD was not proposed as the model of choice for building
downwash analyses. Because PRIME has now been incorporated into AERMOD, the AERMOD
consequence analysis now contains comparisons of the building downwash models. The results,
which are patterned after the earlier ISC-PRIME consequence analysis4, are given in Table 4-4.
Table 4-4 has four sets of columns. The first set of three columns are the scenario
descriptions. The second set of 4 columns include: the maximum annual concentrations from
ISCST3; the ISC-PRIME to ISCST3 annual concentration ratios (which were reported in the earlier
ISC-PRIME consequence analysis); the AERMOD (with PRIME) to ISCST3 annual concentration
ratios; and the AERMOD to ISC-PRIME annual concentration ratios (which are redundant). The
third set of four columns are for the high-second-high 24 hour concentration rations, using the
column structure as for the annual results. The fourth set of four columns are for the high-second-
high 3 hour concentration ratios. Table 4-5 presents the summary statistics for the building
downwash analysis, that is, the maximum, minimum and average concentration ratios for each of the
three averaging times and over all the averaging times.
Table 4-4 makes note of those source/building scenarios where building downwash is
significant. This criterion is based on cavity concentrations. Many source scenarios do not produce
an estimated cavity concentration (e.g. the 100 meter stack separated from the tall building in a rural
setting); but, those that do are marked as significant downwash sources (e.g. the 35 meter stack next
to the squat building in a rural setting). There are two examples where both models generate a
cavity concentration output, but the estimated cavity concentrations are very small (the 100 meter
stack next to the squat building in the urban and rural settings). Table 4-6 presents the summary
statistics of the maximum concentration ratios only for those cases where there is significant
building downwash.
In addition to the downwind concentrations, cavity concentrations are calculated and Table
4-7 presents the results for each source/building scenario. The maximum cavity concentrations from
ISC-PRIME and AERMOD (with PRIME) are given respectively in columns 4 and 5 and the
concentration ratios are seen in column 6. ISCST3 does not contain an algorithm to estimate the
cavity concentration and could not be included in this table. The summary statistics for the
maximum 1 hour cavity concentration ratios are given in Table 4-8.
24
-------
Table 4-4. Building downwash results.
Case Dispersion Stack ISC
(M)
No building (reference) Urban 35 27.1
No building (reference) Rural 35 5.8
No building (reference) Urban 100 3.3
No building (reference) Rural 100 0.4
Squat Building -Stack adjacent to NE of building]
Hb=34; 60x120m * Urban 35 232.6
Hb=34;60x120m* Rural 35 236.6
Hb=50; 60x120m Urban 100 4.1
Hb=50; 60x120m Rural 100 1.5
Squat Building -Stack at distance 4*Hb to NE of building]
Hb=34; 60x120m Urban 35 180.4
Hb=34; 60x120m Rural 35 180.7
Hb=50; 60x120m Urban 100 3.9
Hb=50; 60x120m Rural 100 1.4
Tall Building -Stack adjacent to NE of building]
Hb=34; 30x30m * Urban 35 243.9
Hb=34; 30x30m * Rural 35 242.5
Hb=50; 30x30m Urban 100 3.4
Hb=50; 30x30m Rural 100 0.4
Tall Building -Stack at distance 4*Hb to NE of building]
Hb=34; 30x30m Urban 35 150.8
Hb=34;30x30m Rural 35 181.5
Hb=50; 30x30m Urban 100 3.4
Hb=50; 30x30m Rural 100 0.4
Super Squat Building -Stack adjacent to NE of building]
Hb=34; 180x180m* Urban 35 244.2
Hb=34; 180x180m* Rural 35 243.2
ISCP/
ISC3
1.00
1.00
1.00
1.00
1.23
0.87
2.15
1.61
0.22
0.05
1.09
0.38
1.72
1.32
1.63
1.21
0.26
0.04
1.32
1.06
0.75
0.57
ANNUAL RATIOS
AERMOD/
ISC3
0.65
3.36
0.46
3.76
1.23
1.11
0.77
2.79
0.09
0.12
0.44
1.22
1.35
1.32
0.45
3.66
0.12
0.11
0.45
3.67
0.74
0.69
AERMOD/
ISCP
0.65
3.36
0.46
3.76
ISC
198.8
56.1
22.4
5.1
1.00
1.29
0.36
1.74
1439.8
1574.7
30.0
21.9
0.42
2.46
0.40
3.19
1097.4
1556.5
26.0
17.3
0.79
0.99
0.28
3.03
1508.3
1751.9
23.4
7.5
0.45
2.59
0.34
3.46
1023.5
1556.1
22.7
7.3
0.99
1.23
1508.3
1761.8
ISCP/
ISC3
1.00
1.00
1.00
1.00
1.48
1.03
2.07
1.80
0.25
0.11
1.17
0.32
2.24
1.36
1.60
0.76
0.28
0.05
1.42
0.69
0.90
0.66
24 H2H RATIOS
AERMOD/
ISC3
0.63
2.78
0.53
2.34
1.38
1.16
0.87
1.91
0.11
0.12
0.47
0.71
1.87
1.55
0.51
1.57
0.12
0.10
0.52
1.62
0.86
0.69
AERMOD/
ISCP
0.63
2.78
0.53
2.34
0.93
1.13
0.42
1.06
0.47
1.16
0.40
2.19
0.84
1.14
0.32
2.07
0.43
2.18
0.37
2.34
0.96
1.06
Super Squat Building -Stack at distance 4*Hb to NE of building]
Hb=34; 180x180m Urban 35 226.2
Hb=34; 180x180m Rural 35 240.6
0.17
0.05
0.08
0.10
0.45
2.08
1154.4
1556.5
0.20
0.14
0.14
0.15
0.70
1.04
ISC ISCP/ AERMOD/
ISC3 ISC3
362.4 1.00 0.85
174.7 1.00 2.06
58.6 1.00 0.60
22.6 1.00 1.56
3442.4 0.85 0.79
5662.6 0.39 0.45
62.4 1.93 1.29
59.2 1.62 1.41
3007.7 0.18 0.12
4292.8 0.11 0.10
58.6 1.38 0.65
59.2 0.41 0.64
3442.4 1.29 1.20
5662.6 0.64 0.71
58.6 1.58 0.60
31.3 0.99 1.12
2780.6 0.23 0.11
4206.6 0.07 0.09
58.6 1.45 0.60
31.3 0.76 1.12
3017.8 0.74 0.76
5614.5 0.34 0.38
3007.7 0.16 0.14
4292.8 0.12 0.12
3 H2H RATIOS
AERMOD/
ISCP
0.85
2.06
0.60
1.56
0.93
1.17
0.66
0.87
0.66
0.87
0.47
1.57
0.93
1.11
0.38
1.13
0.47
1.25
0.41
1.48
1.02
1.12
0.85
0.98
Significant downwash
source
25
-------
Table 4-5. Summary of the building downwash analysis.
ALL AVERAGING TIMES
ANNUAL RATIOS
ave
max
min
No cases
ISCP/
ISC3
0.88
2.15
0.04
20
AERMOD/
ISC3
1.03
3.67
0.08
AERMOD/
ISCP
1.38
3.46
0.28
ISCP/
ISC3
0.93
2.24
0.05
20
24 H2H RATIOS
AERMOD/
ISC3
0.82
1.91
0.10
AERMOD/
ISCP
1.06
2.34
0.32
3 H2H RATIOS
ISCP/ AERMOD/
ISC3 ISC3
0.76 0.62
1.93 1.41
0.07 0.09
20
AERMOD/
ISCP
0.92
1.57
0.38
ISCP/
ISC3
0.86
2.24
0.04
60
AERMOD/
ISC3
0.82
3.67
0.08
AERMOD/
ISCP
1.12
3.46
0.28
Table 4-6. Summary of results for those sources with significant downwash.
ANNUAL RATIOS
ave
max
min
No cases
ISCP/
ISC3
1.08
1.72
0.57
6
AERMOD/
ISC3
1.08
1.35
0.69
AERMOD/
ISCP
1.05
1.29
0.79
ISCP/
ISC3
1.28
2.24
0.66
6
24 H2H RATIOS
AERMOD/
ISC3
1.25
1.87
0.69
AERMOD/
ISCP
1.01
1.14
0.84
3 H2H RATIOS
ISCP/ AERMOD/
ISC3 ISC3
0.71 0.71
1.29 1.20
0.34 0.38
6
AERMOD/
ISCP
1.05
1.17
0.93
ISCP/
ISC3
1.02
2.24
0.34
18
ALL AVE RAGING TIMES
AERMOD/
ISC3
1.01
1.87
0.38
AERMOD/
ISCP
1.03
1.29
0.79
26
-------
Table 4-7. Results of the PRIME cavity max hourly concentrations (ug/m3) in ISC-PRIME
and AERMOD (version 02222). Summary statistics of the AERMOD to ISC-PRIME ratios are
included.
Case
No building
No building
No building
No building
Dispersion Stack
(M)
MAX 1 HR CAVITY CONG
AERMOD/
ISCP AERMOD ISCP
Urban
Rural
Urban
Rural
35
35
100
100
Squat Building -Stack adjacent to NE of building
Hb=34; 60x120m Urban 35 3202 3180 0.99
Hb=34; 60x120m Rural 35 2341 3180 1.36
Hb=50; 60x120m Urban 100 10* 0.08* N/A
Hb=50; 60x120m Rural 100 0* 0.08* N/A
Squat Building -Stack at distance 4*Hb to NE of building
Hb=34; 60x120m Urban 35
Hb=34; 60x120m Rural 35
Hb=50; 60x120m Urban 100
Hb=50; 60x120m Rural 100
Tall Building -Stack adjacent to NE of building
Hb=34;30x30m Urban 35 5034 4388 0.87
Hb=34; 30x30m Rural 35 3963 4388 1.11
Hb=50; 30x30m Urban 100
Hb=50; 30x30m Rural 100
Tall Building -Stack at distance 4*Hb to NE of building
Hb=34; 30x30m Urban 35
Hb=34; 30x30m Rural 35
Hb=50; 30x30m Urban 100
Hb=50; 30x30m Rural 100
Super Squat Building -Stack adjacent to NE of building
Hb=34; 180x180m Urban 35 2524 2498 0.99
Hb=34; 180x180m Rural 35 2321 3276 1.41
Super Squat Building -Stack at distance 4*Hb to NE of building
Hb=34; 180x180m Urban 35
Hb=34; 180x180m Rural 35
' considered
insignificant
27
-------
Table 4-8. Summary of the building downwash 1 hour cavity concentration ratios.
ave
max
min
No cases
AERMOD/
ISCP
1.12
1.41
0.87
6
4.3 The Complex Terrain Results.
The complex terrain results which compare AERMOD to ISCST324 and to
CTDMPLUS, are presented in Appendix E. The Appendix E table includes the highest
second high ratios along with the highest annual concentrations. A summary of the complex
terrain results are provided below in Table 4-9. Table 4-9 provides a distribution of
AERMOD to other model concentration ratios. There were no cases where AERMOD
predicted higher concentrations than either ISC or CTDMPLUS. As seen before, the last
column in Table 4-9 provides data, presented in the earlier consequence analysis, as a
convenient reference for the reader.
Table 4-9. Summary statistics based on the ratio of AERMOD predicted regulatory design
concentration to ISCST3(COMPLEX1) and CTDMPIus predicted-regulatory-design concentrations
for complex terrain (see Appendix E).
NO OF RATIOS>4
NO OF RATIOS>3
NO OF RATIOS>2
NO OF RATIOS>1
TOTAL NO
NO OF RATIOS<1 .0
NO OF RATIOS<0.5
NO OF RATIOS<0.33
NO OF RATIOS<0.25
AVERAGE
MAX
MIN
02222AER/
ISC3
0
0
0
0
196
196
189
163
119
0.24
0.79
0.07
02222AER/
CTDM+
0
0
2
40
196
152
58
28
15
0.75
2.13
0.14
02222AER/
99351AER
0
0
1
74
196
77
0
0
0
1.01
2.67
0.61
24In complex terrain, the COMPLEXl portion of the ISCST3 model is playing a significant role. For receptors with
elevations above the plume height, the COMPLEXl concentration estimates are used. In intermediate terrain, the
highest estimates from the "ISCST3" simple terrain model and the COMPLEXl model are used.
28
-------
5. DISCUSSION OF RESULTS
5.1 Discussion of Flat and Simple Terrain Results
5.1.1. The current version of AERMOD (02222). With all the flat and simple terrain
results viewed as a whole, the current version of AERMOD produces maximum
concentrations that are similar to ISCSTS's predicted concentrations. The reported average of
0.96 ( Table 4-1, row 10 column 3) indicates that AERMOD predicts concentrations only
about 4% lower than ISCST3. This average is taken over all source types, stack heights,
settings and concentration averaging times. However, as expected when a new model is
developed, there are differences between the old and the new air dispersion model predictions.
Although about 80% of the AERMOD concentrations are within a factor of 2 (high or low)
from the ISCST3 concentrations Table 4-1, column 3 also indicates that, for certain situations,
the proposed AERMOD predictions are higher or lower than ISCST3 predictions by a factor
of 3 or more. Upon studying column 4 in the detailed Appendix D listing, one can find that
the most significant differences between the 2 models are found in the following scenarios:
1. in the rural, low level stacks (AERMOD is lower);
2. in the long-term concentrations for the rural, taller stacks (AERMOD is higher);
3. in the short-term, urban short stacks and urban area sources (AERMOD is lower); and,
4. in all of the regulatory concentrations for urban very tall stacks in simple terrain
(AERMOD is lower).
These results are consistent across the 2 meteorological data bases. Because the 2 air
dispersion models are significantly different from one another (see Appendix A for side-by-
side comparison), such variation in the model differences is expected.
5.1.2. Impacts of the changes to AERMOD. Changes made to AERMOD produced changes
to the consequence analysis. Column 2 in Table 4-1 shows that, over all source types, settings, and
averaging times, the proposed version of AERMOD predicts an average concentration ratio of 1.14
or about 14% higher than ISCST3 (compared to 0.96 or about 4% lower based on the current
version of AERMOD). Thus, there is about a 16% 25reduction in the overall average of
concentration ratios. Table 4-1 column 3 also indicates that the differences in the AERMOD
predictions are not as extreme as seen in the earlier consequence analysis. The number of cases
where the AERMOD to ISCST3 ratios are greater than a factor of 2 drops from 43 out of a total of
336 (proposed version) to 25 (current version). The number of cases where the concentration ratios
are greater than 3 drops from 12 to 5. On the other side of the distribution where AERMOD
predictions are less than ISCST3's predictions, the distribution of cases where the AERMOD to
The 16% = (1.14-0.96) /1.14 x 100.
29
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ISCST3 concentration ratios are less than one-half, less than one-third and less than one-fourth
remains almost the same as those from the April 1999 analysis.
Reviewing the urban and rural breakout tables (Tables 4-2, 4-3), one sees that the largest
changes occur in the urban setting while the rural distribution and averages do not change
significantly. In the urban setting results in Appendix D, the most significant changes are found in
the following scenarios:
1. in the short-term concentrations for area sources (a decrease in concentrations due to the proper
urbanization of the dispersions parameters);
2. in the short-term concentrations for low stacks (a decrease in concentrations due to the addition
of meander for both stable and unstable settings); and,
3. in the overall urban category when comparing the averages in Table 4-3, row 11, columns 3 and
4 (a decrease due to the addition of stable and unstable urban meander).
In the rural setting, less significant changes are seen and those changes are found:
1. in the short-term concentration for low stacks (an increase due to the changing of the minimum
layer depth used to calculate the effective dispersion parameters- a secondary effect from fixing the
urban dispersion problem); and,
2. in the overall results (a slight overall reduction in concentration predictions due to the addition
of meander in the rural, stable setting).
5.1.3. Model Evaluation Study support. Differences between models leads to the next topic for
discussion - how do these models perform when compared to measured data? Do the differences
represent an improvement in model predictions? The model evaluation study (MES)8 provides
AERMOD's (including the proposed version and the current version) and ISCST3's predictions and
compares them to ambient air quality data. Of the 5 available flat terrain data bases in the MES,
there is one MES site with a low-level release in a flat rural setting. In this scenario, the current
version of AERMOD's (version 02222) short-term concentration predictions (the Robust Highest
Concentrations26 [RHCs]) are about /^ of the ISCST3 estimates, with the AERMOD estimates more
closely matching the observed values. The MES also includes 3 rural, tall stack scenarios in flat or
simple terrain locations which shows AERMOD predicting long-term concentrations (RHCs that
are almost twice as high as the ISCST3 predictions. In all 3 cases, AERMOD predictions are
closer to the measured values. The MES does not have any data bases which are representative of
the shorter stacks in urban settings. The one urban data set (tall stack) in the MES is based on a
limited monitoring study. The urban one-hour RHC for AERMOD is about 20% lower than the
ISCST3 with AERMOD predictions closer to the measured concentrations. The MES supports the
26 W.M. Cox, J.A. Tikvart, "A Statistical Procedure for Determining the Best Performing Air Quality Simulation
Model", Atmospheric Environment, Vol.24A, No 9, pp 2387-2395, 1990
30
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AERMOD concentration predictions over those provided by the ISCST3 model, i.e., AERMOD's
performance is better than ISCSTS's performance when compared to monitored concentrations.
Also, the MES indicates a slight performance improvement when comparing the current
version of AERMOD (version 02222) to the proposed version of AERMOD. The most notable
differences are in the short term concentrations with a tall stack in the urban area and with a tall
stack in moderate hilly terrain in a rural area. In both settings, the current version of AERMOD
predicts lower RHCs than the proposed version (which is consistent with this study) and predicts
concentrations that are closer to the measured values.
5.2 Discussion of Building Downwash Results.
The discussion in this section does not include the proposed version of AERMOD. The
proposed version of AERMOD (99351) does not include the PRIME algorithms and does not play a
role in the building downwash analysis. For this component of the consequence analysis, the
current version of AERMOD (02222) is the new model, ISC-PRIME is the proposed model, and
ISCST3 is the currently approved model.
5.2.1 AERMOD versus ISCST3. Table 4-4 presents the results of the downwash analysis and
Table 4-5 presents a summary of the results. The summary table indicates that AERMOD (with
PRIME) produces somewhat lower maximum concentration estimates, on average, than ISCST3.
The AERMOD to ISCST3 ratios in column 12 displays an average concentration ratio of 0.82;
that is, on average over all 60 cases (10 source types, 2 settings and 3 averaging times), AERMOD
predicts concentrations that are about 18% lower than ISCST3's predictions. However, the range
of the concentration ratios is more significant; AERMOD predicted concentrations that are up to a
factor of 4 higher and up to a factor of 10 lower than ISCST3.
The situation where AERMOD's predicts maximum concentrations much lower than the
ISCST concentrations is found in several cases. For example, the 35 meter stack separated from
the building for all averaging times in urban and rural settings for all 3 building types (total of 18
cases in Table 4-4) indicate lower AERMOD predictions. Because the downwash algorithms in
ISCST3 ignore the separation between stacks and buildings and is designed to be environmentally
conservative27, relatively smaller AERMOD concentrations are expected for the shorter stacks.
This scenario with stack/building separation was chosen originally to highlight the differences in
the ISCST3 and PRIME models, thus, significant differences are expected. The vast majority of
the remaining cases have AERMOD concentrations that are within a factor of 2 of the ISCST3
concentrations.
There are situations where AERMOD is higher than ISCST3. For example, in the annual
concentration estimates for the rural setting, tall and squat building with a 100 meter stack (both
adjacent to the building and separated from the building), the AERMOD maximum concentrations
are larger than the ISCST3 estimates. In these cases, building downwash is not important to the
27ISCST3 assumes that the stack is located in the center of the building which maximizes the impacts of the building
wake on the plume dispersion. Generally, this assumption will predict the highest concentrations.
31
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calculation of maximum annual concentration estimates, so the difference between AERMOD and
ISCST3 concentration estimates are attributable only to the differences in the dispersion algorithms
within the two models. The insignificance of building downwash for these cases is seen: 1) by the
lack of a calculated cavity concentration (Table 4-7); and, by comparing the ISCST3 maximum
concentrations to the matching non-downwash case for 100 meter stack in the rural setting (Table
4-4). The maximum annual concentrations and the concentration ratios for the downwash cases
remains basically unchanged from the corresponding "No building" case.
There is a second set of statistics prepared for those sources where cavity concentrations are
calculated, that is, building downwash is a known significant factor in the dispersion of the plume
(Table 4-6). These sources are marked in Table 4-4. The summary results in column 12, Table 4-
6, show that the AERMOD maximum concentration predictions are, on average, about the same as
those produced by ISCST3 (average concentration ratio of 1.01). The concentration ratios range
from a maximum of 1.87 to a minimum of 0.38. In all these significant downwash cases in Table 4-
4, the stack is close to the building and the discrepancies between the 2 models are due only to the
differences in the downwash algorithms.
5.2.2 AERMOD versus ISC-PRIME. Table 4-5 provides the summary information about the
comparison between AERMOD and ISC-PRIME. Because PRIME is in both models, the
expectation is that the 2 models should be in reasonable agreement. On average over the 60 cases,
the ratio of AERMOD to ISC-PRIME maximum concentration predictions was 1.12 (AERMOD
predictions are about 12% higher than ISC-PRIME predictions), which is rather good agreement.
However, the maximum concentration ratio (3.46) and the minimum concentration ratio ( 0.28) are
of initial concern. When studying the concentration values in Table 4-4 for those cases with the
highest differences (rural case with 100 meter stack separated from a tall building) and lowest
differences (urban case with 100 meter stack near a tall building), one can see that there are similar
differences between the two models in the no-building scenario (rows 3 and 4). Thus, these
extreme cases, which are not significant downwash cases, are mostly explained by the differences
in the dispersion algorithms.
For those cases where building downwash was more important, the two models should be in
closer agreement, because the PRIME algorithms are in both models and should be dominating the
dispersion calculations. Although there are differences in the way that PRIME interacts with the
two dispersion models (the numerical plume rise, the plume capture criteria and blending of the
disturbed plume with the surrounding undisturbed atmosphere), there are a number of tests to check
AERMOD with the PRIME insertion.
The first test involves the cavity concentrations which should be similar between the two
models. Tables 4-7 and 4-8 indicate that this is so. In Table 4-8, for the 6 cases with significant
maximum 1 hour cavity concentrations estimates, the average AERMOD/ISC-PRIME
concentration ratio is 1.12 with the concentration ratio ranging from a maximum of 1.41 to a
minimum of 0.87. These cavity concentration differences are attributable to the differences in the
plume rise equations. There are two cases where a very small cavity concentration is calculated by
32
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both models, but these results not included in the previously mentioned statistics. These two cases
include the 100 meter stack with a squat building in the rural and urban setting.
The second related test reviews the AERMOD versus ISC-PRIME maximum concentration
results for all averaging times for those cases with significant downwash (Table 4-6). The average
AERMOD/ISC-PRIME concentration ratio is 1.03 with a maximum value of 1.29 and a minimum
value of 0.79 (column 13). As expected in these cases with a definite cavity, the two models agree
very closely (plus or minus 30%).
The third test of model consistently compares those cases where building downwash is not
significant enough to produce concentrations different from the reference ("No-building") case (the
first 4 rows in Table 4-4). In this test, both models should predict maximum concentrations that are
essentially the same as those predicted by the model in the corresponding "No building" scenario.
Table 4-4 indicates there are three source scenarios (all averaging times) where the building has
little or no effects on the ISC-PRIME maximum concentrations: rural, urban 100 meter stacks
separated from a squat building; and rural, urban 100 meter stacks near and separated from a tall
building. In all these cases, AERMOD produces a matching result in that the building had almost
no effect on the estimated maximum concentrations.
Conversely, there are cases where AERMOD shows no change from the no-building to the
with building scenario and ISC-PRIME modeling results predict some impact from the building.
Examples of this result are seen in the 3 hour averaging columns: the urban and rural 100 meter
stack near and separated from a tall building; the urban and rural 35 meter stack separated from the
tall building; and, the urban 100 meter stack separated from the tall building. This difference in
the two models is expected because of the critical angle of plume rise used for calculating the
amount of pollution that is caught in the wake of the building. AERMOD development work
suggested a change in this area and a different critical angle was implemented in the AERMOD.
5.2.3. Model Evaluation Study support. The original model evaluation reports13>14, in general,
support the addition of PRIME to the ISCST3 model. The reports conclude that the PRIME had a
statistically better performance result for each data base in the independent evaluation. Although
these results support the implementation of PRIME into the regulatory models, none of the
evaluation databases have examples of stacks significantly separated from the building. So the
model differences cannot be confirmed for this scenario.
Although the AERMOD and ISC-PRIME maximum concentration estimates are in general
agreement, there are differences. Some variations are expected because of the way that PRIME is
integrated into AERMOD. When reviewing the model evaluation results8, one finds that the
AERMOD performance is slightly better than ISC-PRIME. There are four cases of slight
degradation of performance, four cases of similar performance and, five cases with improved
performance. Of the five cases with improved performance, there is one case with a rather
dramatic performance improvement.
33
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5.3 Discussion of Complex Terrain Results.
5.3.1 The current version of AERMOD (02222). The current version of AERMOD (02222)
consistently produced lower or significantly lower regulatory design concentrations estimates than
those generated from the ISCST3 (Table 4-9). This result was expected since that portion of the
ISCST3 model that deals with complex terrain,COMPLEXl, is used for screening purposes and
has been designed to be conservative28. The average AERMOD/ISCST3 concentration ratio,
overall scenarios and averaging times, is 0.24 (column 2, row 10). Thus, AERMOD produced
maximum concentrations that were, over all all cases, a factor of 4 lower than the ISCST3
predictions. The concentration ratios ranged from 0.07 to 0.79. In well over half of the cases (119
of the 196 cases), AERMOD produced maximum concentrations that were a factor of 4 lower than
the ISCST3 estimates. There were no cases where AERMOD predicted maximum concentrations
higher than ISCST3. When examining Appendix E, the differences between the 2 models tended
to increase with averaging time, i.e. the largest differences were seen in the maximum annual
averages.
Also, Table 4-9 and Appendix E contain the results for the AERMOD/CTDMPLUS
comparison. As expected, the models agreed more closely, since CTDMPLUS, which is not a
screening model like COMPLEX1, is a more refined, site-specific complex terrain model. Table 4-
9 indicates that the average AERMOD/CTDMPLUS ratio over all cases was 0.75 with a range of
0.14 (lowest value) to 2.13 (highest value). Table 4-9 indicates that AERMOD predicted
maximum concentrations that were larger than CTDMPLUS in about 20% of cases (40 out of 196).
5.3.2. Impacts of the changes to AERMOD. In the complex terrain scenarios, changes to the
complex terrain algorithms do not produce much of a change to the consequence analysis. Some
minor changes were made to the algorithm to make the model's concentration predictions less
sensitive to the domain selection. The critical value of hill height scale was not changed in the
input files. Thus, significant changes from the earlier consequence analysis are not expected.
Table 4-9 column 4 summarizes the numerical changes to the concentration ratios of the current
version of AERMOD to the proposed version of AERMOD. The average concentration ratio over
all 196 cases is 1.01 which implies that the changes did not bias the model towards higher or lower
concentration estimates. The range of concentration ratios of new versus the old version of
AERMOD was 0.61 to 2.67. The one high value of 2.67 was due to changes in the meander
algorithm and was not a repercussion of the complex terrain changes. Although not shown in the
summary table, about 94 % of the concentration ratios were within a factor of plus or minus 30%.
5.3.3. Model evaluation study support. As mentioned above, the differences between
AERMOD and ISCST3 tend to increase with averaging time, i.e. the largest differences are seen in
the maximum annual averages. These results are confirmed by the complex terrain model
evaluation results. AERMOD consistently predicts lower maximum concentrations than ISCST3
28 That is, the model is designed to overestimate or produce concentration estimates which are larger than
concentrations that one would measure.
34
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with the largest variations occurring in the annual averages. AERMOD provides much better
performance in the complex terrain data bases.
AERMOD does not consistently predict lower maximum concentrations than
CTDMPLUS's estimates, as is seen in the comparisons. There are cases where AERMOD is higher
and lower than the site-specific complex terrain model. These results are consistent with the model
evaluation results as AERMOD produces RHCs higher and lower than CTDMPLUS. However, in
all but one of the 10 evaluation cases, AERMOD outperforms CTDMPLUS.
The model evaluation results indicate that the current version of the model performs slightly
better than the proposed version. In all of the 10 complex terrain database cases, the change to the
performance is no greater than 9%.
35
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6. GENERAL CONCLUSIONS
The following general conclusions are made.
1) For non-downwash settings in flat and simple terrain, the current version of AERMOD (version
02222): a) on average, tends to predict maximum concentrations that are similar to ISCST3; b) ,
on average, tends to predict concentrations closer to ISCST3 than the proposed version of
AERMOD; and, c) predicts maximum concentrations which are not as extreme in their differences
from ISCST3 as those seen when applying the proposed version of AERMOD; and, on average,
tends to predict urban maximum concentrations that are lower than the proposed version of
AERMOD.
2) Where building downwash is a significant factor in the air dispersion analysis, the current
version of AERMOD predicts maximum concentrations and maximum cavity concentrations that
are very similar to ISC-PRIME.
3) In general, the consequences from using the current version of AERMOD instead of ISCST3 in
complex terrain are significant, the current version of AERMOD produces much lower maximum
concentrations than the screening technique in ISCST3. Also, the current version of AERMOD
produced results that are essentially unchanged from the results reported using the proposed version
of AERMOD. When compared to CTDMPLUS, AERMOD tends to predict somewhat lower
maximum concentrations with examples of AERMOD predictions being higher and lower than the
CTDMPLUS predictions.
4) Where data are available, the model evaluation results support the differences identified in this
report when comparing the proposed version of AERMOD to ISCST3 and when comparing the
current version of AERMOD to the proposed version of AERMOD. . The model evaluation report
indicates that the current version of AERMOD outperforms all the other four models ( ISCST3,
ISC-PRIME, CDTMPLUS and the proposed version of AERMOD).
5) Because of the stability of AERMOD model throughout the consequence analysis and because the
model evaluation study supports AERMOD (02222) when significant differences occur between the
current version of AERMOD and ISCST3 or the earlier version of AERMOD, it is appropriate for
the Agency to adopt the current version of AERMOD (02222) as a regulatory model and is a
suitable replacement for ISCST3 for many regulatory applications.
36
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7. COMPUTER RUN TIMES
As an additional feature to the consequence analysis, ISCST3 and AERMOD models were
compiled and run on a typical personal computer. The purpose of this exercise was to provide the
user community with a sense of the potential changes in the amount of time to run typical source
configurations on their computer systems. The results are tabulated below in Table 7-1. The
computer used to complete this table was a Pentium 2.4 Gigahertz computer with 256 megabytes of
random access memory. Each source run evaluated 180 receptors in a polar grid (36 radials with 5
ring distances). One full year (8784 hours) of meteorological data was used for each run.
Table 7-1. Computer Run Times for Typical Source Configurations.
Source Type
Point source
Point source w/ downwash
Volume source
Area source
AERMOD
20.1 seconds
179
12.8
2190
ISCST3
2.34 seconds
42
2.03
515
AERTSC
RATIO
8.5
4.1
6.3
4.3
37
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APPENDIX A
SIDE BY SIDE COMPARISON
AERMOD VERSUS ISCST3
38
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Feature
ISCST3
AERMOD (version 02222)
Comments
Types of sources
modeled
Point, area, and
volume sources
Same as ISCST3
Models are comparable
Plume Rise
Uses Briggs equations
with stack-top wind
speed and vertical
temperature gradient
In stable conditions, uses Briggs
equations with winds and
temperature gradient at stack top
and half-way to final plume rise;
in convective conditions, plume
rise is superposed on the
displacements by random convective
velocities
AERMOD is better because in
stable conditions it factors in
wind and temperature changes
above stack top, and in
unstable conditions it accounts
for convective updrafts and
downdrafts
Meteorological Data
Input
One level of data
accepted
An arbitrarily large number of data
levels can be accommodated
AERMOD can adapt multiple
levels of data to various stack
and plume height
Profiling
Meteorological Data
Only wind speed is
profiled
AERMOD creates profiles of wind,
temperature, and turbulence, using
all available measurement levels
AERMOD is much improved over
ISCST3 in this area
Use of
Meteorological Data
in Plume Dispersion
Stack-top variables
for all downwind
distances
Variables measured throughout the
plume depth (averaged from plume
centerline to 2.15 sigma-z below
centerline; changes with downwind
distance)
AERMOD treatment is far more
advanced than that of ISCST3;
accounts for meteorological
data throughout the plume depth
Plume Dispersion:
General Treatment
Gaussian treatment in
horizontal and
vertical
Gaussian treatment in horizontal
and in vertical for stable
conditions; non-Gaussian
probability density function in
vertical for unstable conditions
AERMOD's unstable treatment of
vertical dispersion is a more
accurate portrayal of actual
conditions
39
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Feature
ISCST3
AERMOD (version 02222)
Comments
Urban Treatment
Urban option either
on or off; no other
specification
available; all
sources must be
modeled either rural
or urban
Population is specified, so
treatment can consider a variety of
urban conditions; sources can
individually be modeled rural or
urban
AERMOD provides variable urban
treatment as a function of city
population, and can selectively
model sources as rural or urban
Characterization of
Modeling Domain
Surface
Characteristics
Choice of rural or
urban
Selection by direction and month of
roughness length, albedo, and Bowen
ratio, providing user flexibility
to vary surface characteristics
AERMOD provides the user with
considerably more options in
the selection of the surface
characteristics
Boundary Layer
Parameters
Wind speed, mixing
height, and stability
class
Friction velocity, Monin-Obukhov
length, convective velocity scale,
mechanical and convective mixing
height, sensible heat flux
AERMOD provides parameters
required for use with up-to-
date planetary boundary layer
(PEL) parameterizations; ISCST3
does not
Mixed Layer Height
Holzworth scheme;
uses interpolation
based upon maximum
afternoon mixing
height
Has convective and mechanical mixed
layer height; convective height
based upon hourly accumulation of
sensible heat flux
AERMOD's formulation is
significantly more advanced
than that of ISCST3, includes a
mechanical component, and in
using hourly input data,
provides a more realistic
sequence of the diurnal mixing
height changes
40
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Feature
ISCST3
AERMOD (version 02222)
Comments
Terrain Depiction
Elevation at each
receptor point
Controlling hill elevation and
point elevation at each receptor,
obtained from special terrain pre-
processor (AERMAP) that uses
digital elevation model (DEM) data
AERMOD's terrain pre-processor
provides information for
advanced critical dividing
streamline height algorithms
and uses digital data to obtain
receptor elevations
Plume Dispersion:
Plume Growth Rates
Based upon 6 discrete
stability classes
only; dispersion
curves (Pasquill-
Gifford) are based
upon surface release
experiments (e.g..
Prairie Grass)
Uses profiles of vertical and
horizontal turbulence (from
measurements and/or PEL theory);
variable with height; uses
continuous growth functions rather
than a discrete (stability-based)
formulation
Use of turbulence-based plume
growth with height dependence
rather than that based upon
stability class provides AERMOD
with a substantial advancement
over the ISCST3 treatment
Plume Interaction
with Mixing Lid:
convective
conditions
If plume centerline
is above lid, a zero
ground-level
concentration is
assumed
Three plume components are
considered: a "direct" plume that
is advected to the ground in a
downdraft, an "indirect" plume
caught in an updraft that reaches
the lid and eventually is brought
to the ground, and a plume that
penetrates the mixing lid and
disperses more slowly in the stable
layer aloft (and which can re-enter
The AERMOD treatment avoids
potential underpredictions
suffered by ISCST3 due to its
"all or nothing" treatment of
the plume; AERMOD's use of
convective updrafts and
downdrafts in a probability
density function approach is a
significant advancement over
ISCST3
41
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Feature
Plume Interaction
with Mixing Lid:
stable conditions
Building Downwash
ISCST3
The mixing lid is
ignored (assumed to
be infinitely high)
Combination of Huber-
Snyder and Scire-
Schulman algorithms;
many discontinuities
AERMOD (version 02222)
the mixed layer and disperse to the
ground)
A mechanically mixed layer near the
ground is considered. Plume
reflection from an elevated lid is
considered.
New PRIME downwash algorithm
installed
Comments
AERMOD' s use of a mechanically
mixed layer is an advancement
over the very simplistic ISCST3
approach
AERMOD benefits from the
technological advances offered
by the PRIME model
This page left intentionally blank.
42
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APPENDIX B
FIGURES FOR DESCRIBING COMPLEX
TERRAIN
-------
lished Qlipses. Prgss ENTER IPIEPHNTB - unedited |
t Kn.
Figure B-l. Plot of Piedmont Hill Contours.
44
-------
TERRAIN INFORMATION
HILL NAMED PIEDMONT HILL TOP: 2240.0 feet
Figure B-l displays both actual and transformed contours for the Piedmont hill. The
transformed contours were used in the modeling analysis. There are 2 sets of 13 contours;
the dotted lines are the actual contours and the solid lines are the transformed or modeled
contours. The elevations for the 13 contours are listed below:
1000.0 feet
1100.0
1200.0
1300.0
1400.0
1500.0
1600.0
1700.0
1800.0
1900.0
2000.0
2100.0
The actual receptor locations are listed in the AERMOD control files which are listed in
Appendix C.
45
-------
Finished QlipsQs.
CNTEP IHONTDUR - Unedited)
1 KM
Figure B-2. Plot of Montour Ridge Contours.
46
-------
TERRAIN INFORMATION
HILL NAMED MONTOUR HILLTOP: 1429.0 meters
Figure B-2 displays both actual and transformed contours for the Montour Ridge. The
transformed contours were used in the modeling analysis. There are 2 sets of 8 contours; the
dotted lines are the actual contours and the solid lines are the transformed or modeled
contours. The elevations for the 8 contours are listed below:
700.0 meters
800.0
900.0
1000.0
1100.0
1200.0
1300.0
1400.0
The actual receptor locations are listed in the AERMOD control files which are listed in
Appendix C.
47
-------
u
Ol
W
D.
ol
o
U
33
o
U
•B
o
PH
fi
(C
-------
TERRAIN INFORMATION
HILL NAMED CINDER CONE BUTTE (CCB) HILL TOP: 100.0 meters
Figure B-3 displays both actual and transformed contours for CCB. The transformed
contours were used in the modeling analysis. There are 2 sets of 11 contours; the dotted lines
are the actual contours and the solid lines are the transformed or modeled contours. The
elevations for the 11 contours are listed below:
0.0 meters
5.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
The actual receptor locations are listed in the AERMOD control files which are listed in
Appendix C.
-------
APPENDIX C
LOCATION OF SOURCE AND RECEPTORS
FOR THE COMPLEX TERRAIN ANALYSIS
50
-------
** Cinder Cone Butte
** Low Stack Height: 30 meters
** High Buoyancy Case: 6-m diameter, 30 m/s Exit Vel, 500 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
** Cinder Cone Butte
** Low Stack Height: 30 meters
** High Buoyancy Case: 6-m diameter, 30 m/s Exit Vel, 500 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
**
CO STARTING
TITLEONE Cinder Cone Butte: Source 1 km away
TITLETWO 30-m Stack Height; High Buoyancy Case
MODELOPT CONG MSGPRO
AVERTIME 1 3 24 Period
POLLUTID SO2
RUNORNOT RUN
ERRORFIL ERRORS.OUT
TERRHGTS ELEV
CO FINISHED
SO STARTING
ELEVUNIT FEET
LOCATION STACK1 POINT
** Point Source QS
** Parameters:
SRCPARAM STACK1 1.
0.0 1500.0 3100.0
HS TS VS DS
30. 500. 30.0 6.0
SRCGROUP ALL
SO FINISHED
RE
RE
**
RE
RE
RE
RE
RE
RE
RE
STARTING
ELEVUNIT
FEET
X (meters) y (meters)
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
2
-88
-164
-222
-258
-288
-287
.00
.98
.25
.04
.22
.26
.25
-302.
-269.
-208.
-130.
-40.
51.
147.
00
90
74
75
01
90
62
z (feet)
3198
3198
3198
3198
3198
3198
3198
.42
.42
.42
.42
.42
.42
.42
3395
3395
3395
3395
3395
3395
3395
.27
.27
.27
.27
.27
.27
.27
51
-------
** Cinder Cone Butte
** Low Stack Height: 30 meters
High Buoyancy Case: 6-m diameter, 30 m/s Exit Vel, 500 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
-241.
-146.
-98.
-11.
78.
154.
211.
256.
196.
202.
253.
190.
103.
2.
-79.
-146.
-198.
-232.
-261.
-267.
-230.
-146.
-91.
-26.
55.
126.
179.
202.
162.
151.
201.
176.
97.
2.
-71.
-131.
-178.
83
77
96
03
05
00
91
99
67
01
73
44
16
00
33
86
80
68
87
17
33
35
21
62
30
01
34
47
42
72
61
30
36
00
09
43
05
223.
217.
288.
302.
263.
201.
123.
38.
-33.
-107.
-185.
-256.
-295.
-278.
-250.
-196.
-127.
-47.
34.
121.
194.
179.
229.
275.
248.
197.
129.
52.
-23.
-91.
-163.
-232.
-267.
-251.
-230.
-182.
-120.
90
43
04
58
18
72
27
11
00
64
45
50
08
00
67
29
07
04
64
16
77
65
83
52
31
64
32
18
57
57
01
57
36
00
09
39
85
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3198.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3231.
3264.
3264.
3264.
3264.
42
42
42
42
42
42
42
42
42
42
42
42
42
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
04
04
04
04
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
52
-------
** Cinder Cone Butte
** Low Stack Height: 30 meters
High Buoyancy Case: 6-m diameter, 30 m/s Exit Vel, 500 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
-201.
-230.
-237.
-214.
-140.
-81.
-31.
41.
105.
155.
163.
135.
113.
149.
151.
84.
2.
-61.
-114.
-153.
-180.
-206.
-215.
-195.
-129.
-74.
-32.
31.
86.
130.
136.
114.
85.
106.
125.
73.
3.
61
06
00
19
21
40
28
60
42
35
34
40
60
22
97
02
00
01
04
87
97
06
00
31
76
20
19
93
72
34
25
98
47
04
03
77
00
-47.
24.
100.
169.
150.
187.
243.
231.
187.
129.
61.
-9.
-71.
-140.
-204.
-240.
-231.
-208.
-168.
-115.
-54.
7.
73.
130.
120.
152.
204.
209.
172.
123.
61.
-2.
-49.
-113.
-175.
-215.
-206.
29
39
64
15
71
62
37
33
96
97
63
50
80
06
88
37
00
49
94
63
34
87
91
00
63
79
87
23
28
48
17
29
87
29
86
85
00
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3264
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3296
3329
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.04
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.85
.66
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
53
-------
** Cinder Cone Butte
** Low Stack Height: 30 meters
High Buoyancy Case: 6-m diameter, 30 m/s Exit Vel, 500 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
-53.
-99.
-134.
-159.
-179.
-187.
-156.
-99.
-55.
-17.
36.
83.
114.
104.
72.
50.
69.
88.
65.
2.
-51.
-94.
-127.
-143.
-161.
-125.
-72.
-32.
7.
59.
87.
83.
41.
-12.
-54.
-17.
36.
07
24
94
94
33
72
80
24
52
95
11
25
87
12
48
78
73
06
18
00
36
97
05
69
36
43
68
04
68
05
00
26
54
50
22
83
25
-188.
-153.
-107.
-54.
1.
58.
93.
95.
134.
179.
181.
147.
99.
42.
-4.
-31.
-83.
-138.
-187.
-181.
-161.
-124.
-78.
-23.
30.
62.
83.
122.
162.
141.
94.
38.
8.
25.
2.
-30.
-48.
80
39
29
13
32
87
46
55
37
52
51
75
51
87
28
31
64
92
19
00
23
59
21
72
37
70
20
40
36
43
58
04
84
13
65
31
00
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3329
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
3362
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.66
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
.46
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
54
-------
** Cinder Cone Butte
** Low Stack Height: 30 meters
High Buoyancy Case: 6-m diameter, 30 m/s Exit Vel, 500 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
52
57
4
-22
-46
-67
-82
-88
-66
-40
-14
10
23
23
7
15
3
9
34
55
65
57
.65
.52
.00
.33
.82
.86
.70
.59
.55
.90
.47
.97
.83
.86
.13
.65
.80
.99
.87
.86
.52
.11
-100.
-155.
-146.
-143.
-133.
-117.
-95.
-70.
-64.
-69.
-72.
-79.
-101.
-127.
-144.
73.
96.
119.
124.
108.
85.
61.
60
07
00
15
11
36
60
00
01
61
14
29
15
28
96
30
84
90
11
49
47
70
3362
3362
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
.46
.46
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
3395
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
.27
RE FINISHED
ME STARTING
SURFFILE SURFACE FREE
PROFFILE PROFILE FREE
SURFDATA 99999 1994 Tower/Sodar
UAIRDATA 99999 1994 Tower/Sodar
SITEDATA 00000 1994 Tower/Sodar
ME FINISHED
OU STARTING
RECTABLE ALLAVE FIRST-SECOND
OU FINISHED
55
-------
** Montour Alongwind Hill
** High Stack Height: 150 meters
** Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
** Montour Alongwind Hill
** High Stack Height: 150 meters
** Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
**
CO STARTING
TITLEONE Montour Alongwind Hill: Source 1 km away
TITLETWO 150-m Stack Height; Low Buoyancy Case
MODELOPT CONG MSGPRO
1 3 24 Period
S02
RUN
ERRORS.OUT
ELEV
AVERTIME
POLLUTID
RUNORNOT
ERRORFIL
** TERRHGTS
CO FINISHED
SO STARTING
ELEVUNIT FEET
LOCATION STACK1
** Point Source
** Parameters:
SRCPARAM STACK1
POINT
QS
-3500.0
HS TS
0.0
VS
700.0
DS
1. 150. 400. 10.0 2.0
SRCGROUP ALL
SO FINISHED
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
STARTING
ELEVUNIT
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
FEET
1655
1075
481
-125
-747
-1367
-1332
-761
.00
.54
.15
.99
.97
.68
.89
.22
146
-98
-308
-475
-576
-518
-67
195
.00
.85
.48
.98
.12
.96
.94
.56
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
00
00
00
00
00
00
00
00
1400
1400
1400
1400
1400
1400
1400
1400
56
-------
** Montour Alongwind Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
-149
465
1093
1712
2281
2905
3514
4142
4040
3413
2851
2224
141
-108
-358
-607
-857
-1083
-1074
-875
-637
-395
-152
92
342
592
843
1081
1102
886
649
420
-373
-287
-188
-89
9
.69
.45
.57
.61
.57
.52
.58
.81
.15
.23
.31
.11
.00
.32
.91
.97
.60
.05
.53
.96
.92
.29
.75
.72
.50
.42
.23
.96
.55
.71
.92
.08
.00
.24
.10
.24
.09
347
485
506
443
691
783
925
947
665
607
427
416
-299
-341
-376
-421
-453
-366
-137
10
95
168
240
301
342
378
366
287
95
-29
-118
-223
-31
27
58
90
119
.21
.10
.82
.97
.14
.48
.91
.59
.33
.18
.99
.49
.00
.14
.51
.69
.09
.88
.83
.86
.96
.10
.59
.83
.65
.00
.02
.07
.11
.07
.37
.10
.00
.50
.73
.31
.15
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1400.
1400.
1400.
1400.
1400.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
57
-------
** Montour Alongwind Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
113
214
311
410
405
337
244
152
53
-48
-151
-253
-354
-450
-460
.04
.03
.84
.80
.63
.71
.77
.08
.15
.48
.63
.71
.07
.53
.63
125
144
177
157
69
-8
-55
-102
-132
-155
-169
-189
-217
-194
-106
.22
.82
.82
.11
.59
.29
.12
.54
.88
.28
.15
.72
.34
.01
.35
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
RE FINISHED
ME STARTING
SURFFILE SURFACE FREE
PROFFILE PROFILE FREE
SURFDATA 99999 1994 Tower/Sodar
UAIRDATA 99999 1994 Tower/Sodar
SITEDATA 00000 1994 Tower/Sodar
PROFBASE 0
ME FINISHED
OU STARTING
RECTABLE
OU FINISHED
ALLAVE FIRST-SECOND
58
-------
** Montour Crosswind Hill
** High Stack Height: 150 meters
** Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
** Montour Crosswind Hill
** High Stack Height: 150 meters
** Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
**
CO STARTING
TITLEONE Montour Crosswind Hill: Source 1 km away
TITLETWO 150-m Stack Height; Low Buoyancy Case
MODELOPT CONG MSGPRO
1 3 24 Period
S02
RUN
ERRORS.OUT
ELEV
AVERTIME
POLLUTID
RUNORNOT
ERRORFIL
** TERRHGTS
CO FINISHED
SO STARTING
ELEVUNIT FEET
LOCATION STACK1
** Point Source
** Parameters:
SRCPARAM STACK1
POINT 0.0 2000.0 700.0
QS HS TS VS DS
1. 150. 400. 10.0 2.0
SRCGROUP ALL
SO FINISHED
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
STARTING
ELEVUNIT
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
FEET
1655
1075
481
-125
-747
-1367
-1332
-761
.00
.54
.15
.99
.97
.68
.89
.22
146
-98
-308
-475
-576
-518
-67
195
.00
.85
.48
.98
.12
.96
.94
.56
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
00
00
00
00
00
00
00
00
1400
1400
1400
1400
1400
1400
1400
1400
59
-------
** Montour Crosswind Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
-149
465
1093
1712
2281
2905
3514
4142
4040
3413
2851
2224
141
-108
-358
-607
-857
-1083
-1074
-875
-637
-395
-152
92
342
592
843
1081
1102
886
649
420
-373
-287
-188
-89
9
.69
.45
.57
.61
.57
.52
.58
.81
.15
.23
.31
.11
.00
.32
.91
.97
.60
.05
.53
.96
.92
.29
.75
.72
.50
.42
.23
.96
.55
.71
.92
.08
.00
.24
.10
.24
.09
347
485
506
443
691
783
925
947
665
607
427
416
-299
-341
-376
-421
-453
-366
-137
10
95
168
240
301
342
378
366
287
95
-29
-118
-223
-31
27
58
90
119
.21
.10
.82
.97
.14
.48
.91
.59
.33
.18
.99
.49
.00
.14
.51
.69
.09
.88
.83
.86
.96
.10
.59
.83
.65
.00
.02
.07
.11
.07
.37
.10
.00
.50
.73
.31
.15
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1200.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1300.
1400.
1400.
1400.
1400.
1400.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
60
-------
** Montour Crosswind Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
113
214
311
410
405
337
244
152
53
-48
-151
-253
-354
-450
-460
.04
.03
.84
.80
.63
.71
.77
.08
.15
.48
.63
.71
.07
.53
.63
125
144
177
157
69
-8
-55
-102
-132
-155
-169
-189
-217
-194
-106
.22
.82
.82
.11
.59
.29
.12
.54
.88
.28
.15
.72
.34
.01
.35
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
1400.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
1400
RE FINISHED
ME STARTING
SURFFILE SURFACE FREE
PROFFILE PROFILE FREE
SURFDATA 99999 1994 Tower/Sodar
UAIRDATA 99999 1994 Tower/Sodar
SITEDATA 00000 1994 Tower/Sodar
PROFBASE 0
ME FINISHED
OU STARTING
RECTABLE
OU FINISHED
ALLAVE FIRST-SECOND
61
-------
** Piedmont Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
** Piedmont Hill
** High Stack Height:
** Low Buoyancy Case:
150 meters
2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
CO STARTING
TITLEONE
TITLETWO
MODELOPT
AVERTIME
POLLUTID
RUNORNOT
ERRORFIL
** TERRHGTS
CO FINISHED
Piedmont Hill: Source 1 km away
150-m Stack Height; Low Buoyancy Case
CONG MSGPRO
1 3 24 Period
S02
RUN
ERRORS.OUT
ELEV
SO STARTING
ELEVUNIT FEET
LOCATION STACK1
** Point Source
** Parameters:
SRCPARAM STACK1
POINT 0.0 1000.0 1000.0
QS HS TS VS DS
1. 150. 400. 10.0 2.0
SRCGROUP ALL
SO FINISHED
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
STARTING
ELEVUNIT
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
FEET
-612
-632
-495
-433
-106
245
413
553
.40
.69
.55
.60
.68
.80
.78
.12
-1792
-1395
-1025
-668
-522
-585
-230
138
.00
.44
.07
.18
.37
.23
.98
.16
1500
1500
1500
1500
1500
1500
1500
1500
.00
.00
.00
.00
.00
.00
.00
.00
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
00
00
00
00
00
00
00
00
62
-------
** Piedmont Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
882.
1211.
1277.
1032.
-582.
-561.
-479.
-341.
-133.
242.
448.
592.
918.
1228.
1088.
885.
-505.
-480.
-465.
-310.
-138.
231.
469.
618.
944.
1164.
962.
783.
-357.
-437.
-369.
-285.
-166.
192.
486.
638.
945.
78
30
72
05
60
02
65
53
80
75
16
43
60
23
95
35
50
41
41
06
32
42
14
92
57
28
35
63
70
57
41
45
77
72
38
29
65
337.
132.
-198.
-511.
-2015.
-1616.
-1223.
-863.
-612.
-647.
-311.
59.
238.
4.
-350.
-698.
-2155.
-1760.
-1358.
-987.
-654.
-710.
-408.
-32.
168.
-117.
-467.
-831.
-2305.
-1945.
-1566.
-1172.
-788.
-801.
-562.
-189.
31.
97
16
82
55
00
37
82
47
84
07
09
94
86
15
46
68
00
47
34
10
32
58
24
23
79
76
47
20
00
98
25
66
53
51
30
10
54
1500
1500
1500
1500
1600
1600
1600
1600
1600
1600
1600
1600
1600
1600
1600
1600
1700
1700
1700
1700
1700
1700
1700
1700
1700
1700
1700
1700
1800
1800
1800
1800
1800
1800
1800
1800
1800
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
63
-------
** Piedmont Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
1040.
845.
700.
-312.
-352.
-284.
-219.
-103.
231.
526.
675.
957.
856.
728.
646.
-211.
-208.
-103.
-133.
-159.
-71.
67.
296.
524.
573.
607.
677.
99.
52.
34.
93.
-9.
2.
127.
276.
443.
421.
60
76
78
10
85
39
41
65
54
84
48
97
22
44
54
00
98
15
27
02
30
68
79
56
38
64
99
85
53
82
40
02
67
68
83
05
80
-246.
-601.
-978.
-2275.
-1926.
-1572.
-1204.
-845.
-848.
-634.
-292.
-77.
-432.
-787.
-1155.
-2248.
-2019.
-1812.
-1588.
-1357.
-1142.
-957.
-912.
-859.
-1049.
-1272.
-1493.
-2515.
-2279.
-2043.
-1816.
-1599.
-1394.
-1190.
-1010.
-1102.
-1337.
59
19
55
00
16
42
49
19
17
35
95
44
11
98
69
00
81
17
07
53
46
10
52
69
63
62
23
00
43
20
61
99
18
55
06
06
79
1800
1800
1800
1900
1900
1900
1900
1900
1900
1900
1900
1900
1900
1900
1900
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2100
2100
2100
2100
2100
2100
2100
2100
2100
2100
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
64
-------
** Piedmont Hill
** High Stack Height: 150 meters
Low Buoyancy Case: 2-m diameter, 10 m/s Exit Vel, 400 K
** Close to Hill: 1 km away
** Meteorology from 100-m Tower and Sodar
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
RE
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
DISCCART
613
643
348
323
375
308
340
409
387
296
440
552
606
666
.92
.13
.70
.75
.69
.07
.42
.93
.04
.38
.59
.40
.70
.27
-1451.
-1689.
-2665.
-2501.
-2350.
-2194.
-2038.
-1883.
-1722.
-1584.
-1521.
-1613.
-1773.
-1932.
98
91
00
71
23
93
55
47
33
62
57
29
86
25
2100
2100
2200
2200
2200
2200
2200
2200
2200
2200
2200
2200
2200
2200
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
2200.
00
00
00
00
00
00
00
00
00
00
00
00
00
00
RE FINISHED
ME STARTING
SURFFILE SURFACE FREE
PROFFILE PROFILE FREE
SURFDATA 99999 1994 Tower/Sodar
UAIRDATA 99999 1994 Tower/Sodar
SITEDATA 00000 1994 Tower/Sodar
PROFBASE 0
ME FINISHED
OU STARTING
RECTABLE
OU FINISHED
ALLAVE FIRST-SECOND
65
-------
APPENDIX D
FLAT AND SIMPLE TERRAIN MODELING RESULTS -
LISTING OF REGULATORY DESIGN CONCENTRATIONS
66
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
R05NDNBO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R05NDNBP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R10NDNBO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R10NDNBP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
1.477E+06
1.477E+06
9.403E+05
6.626E+05
1.678E+05
1.355E+05
1.537E+04
ISC3
2.215E+06
1.477E+06
8.294E+05
6.729E+05
3.350E+05
1.503E+05
9.266E+03
ISC3
8.679E+05
8.679E+05
5.524E+05
3.918E+05
1.018E+05
8.792E+04
1.147E+04
ISC3
1.283E+06
8.679E+05
4.871 E+05
3.966E+05
2.044E+05
9.117E+04
7.044E+03
99351AER/
ISC3
0.434
0.432
0.454
0.461
0.539
0.591
0.388
99351AER/
ISC3
0.357
0.433
0.608
0.427
0.347
0.472
0.500
99351AER/
ISC3
0.442
0.440
0.484
0.574
0.694
0.645
0.515
99351AER/
ISC3
0.355
0.441
0.706
0.542
0.399
0.550
0.615
02222AER/
ISC3
0.673
0.668
0.688
0.574
0.596
0.730
0.434
02222AER/
ISC3
0.619
0.671
0.783
0.629
0.510
0.687
0.593
02222AER/
ISC3
0.504
0.502
0.541
0.591
0.592
0.605
0.529
02222AER/
ISC3
0.410
0.503
0.764
0.546
0.438
0.613
0.661
02222AER/
99351AER
1.550
1.546
1.516
1.244
1.106
1.235
1.119
02222AER/
99351AER
1.734
1.548
1.288
1.473
1.470
1.455
1.185
02222AER/
99351AER
1.139
1.140
1.118
1.030
0.852
0.937
1.027
02222AER/
99351AER
1.155
1.140
1.082
1.009
1.098
1.115
1.075
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
67
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
R20NDNBO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R20NDNBP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R35MFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R35MFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
7.518E+04
5.041 E+04
3.027E+04
1.975E+04
8.005E+03
5.218E+03
8.692E+02
ISC3
7.595E+04
4.889E+04
3.242E+04
2.192E+04
7.737E+03
6.170E+03
6.952E+02
ISC3
1.394E+03
1.257E+03
1.091E+03
9.733E+02
3.291 E+02
3.022E+02
4.046E+01
ISC3
1.394E+03
1.267E+03
9.518E+02
7.229E+02
3.393E+02
2.322E+02
2.781 E+01
99351AER/
ISC3
0.510
0.551
0.735
0.875
1.076
1.496
2.277
99351AER/
ISC3
0.524
0.709
0.745
0.835
1.207
1.254
1.926
99351AER/
ISC3
1.093
1.103
0.971
0.932
1.624
1.723
2.005
99351AER/
ISC3
1.215
1.193
1.207
1.181
1.206
1.295
1.835
02222AER/
ISC3
0.480
0.602
0.621
0.850
1.052
1.417
2.269
02222AER/
ISC3
0.508
0.618
0.682
0.767
1.166
1.242
1.931
02222AER/
ISC3
1.652
1.192
0.989
0.932
1.581
1.689
2.002
02222AER/
ISC3
1.823
1.326
1.154
1.087
1.262
1.260
1.815
02222AER/
99351AER
0.941
1.092
0.846
0.971
0.978
0.947
0.996
02222AER/
99351AER
0.970
0.873
0.916
0.918
0.966
0.990
1.002
02222AER/
99351AER
1.511
1.081
1.019
1.000
0.974
0.980
0.998
02222AER/
99351AER
1.500
1.111
0.956
0.920
1.046
0.97
0.989
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
68
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
R35BFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R35BFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R100FO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R100FP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
2.651 E+02
2.551 E+02
1.832E+02
1.807E+02
8.005E+01
6.871 E+01
8.103E+00
ISC3
2.626E+02
2.608E+02
1.951 E+02
1.394E+02
6.414E+01
5.184E+01
5.464E+00
ISC3
6.150E+01
5.391 E+01
3.820E+01
2.791 E+01
6.271 E+00
5.537E+00
6.320E-01
ISC3
5.296E+01
5.003E+01
2.751 E+01
1.826E+01
7.965E+00
4.170E+00
4.000E-01
99351AER/
ISC3
1.589
1.623
2.142
2.081
2.534
2.721
3.121
99351AER/
ISC3
1.575
1.537
2.006
2.411
2.650
2.995
3.388
99351AER/
ISC3
0.917
0.901
1.153
1.413
2.107
2.347
2.696
99351AER/
ISC3
0.931
0.925
1.474
1.907
1.759
2.628
3.253
02222AER/
ISC3
1.589
1.622
2.142
2.081
2.463
2.714
3.054
02222AER/
ISC3
1.575
1.537
2.006
2.411
2.618
2.936
3.322
02222AER/
ISC3
0.816
0.805
1.020
1.290
2.128
2.313
2.663
02222AER/
ISC3
0.815
0.816
1.309
1.724
1.622
2.395
3.203
02222AER/
99351AER
1.000
1.000
1.000
1.000
0.972
0.998
0.979
02222AER/
99351AER
1.000
1.000
1.000
1.000
0.988
0.980
0.981
02222AER/
99351AER
0.889
0.894
0.884
0.913
1.010
0.986
0.988
02222AER/
99351AER
0.875
0.882
0.888
0.904
0.922
0.911
0.985
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
69
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
R200FO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R200FP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R35TO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R35TP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
3.441 E+01
2.074E+01
1.335E+01
1.043E+01
2.594E+00
1.907E+00
1.480E-01
ISC3
3.479E+01
3.1 31 E+01
1.160E+01
1.098E+01
3.174E+00
1.714E+00
8.200E-02
ISC3
2.863E+02
2.522E+02
1.606E+02
1.471E+02
5.868E+01
5.074E+01
6.466E+00
ISC3
2.984E+02
2.835E+02
2.087E+02
1.668E+02
6.858E+01
5.750E+01
6.193E+00
99351AER/
ISC3
1.036
0.989
1.212
1.044
1.414
1.781
3.162
99351AER/
ISC3
0.836
0.583
1.015
0.886
1.223
1.824
3.890
99351AER/
ISC3
1.111
1.255
1.903
2.039
3.151
3.411
3.394
99351AER/
ISC3
1.040
1.085
1.366
1.694
2.141
2.227
2.289
02222AER/
ISC3
0.941
0.922
1.091
0.929
1.328
1.716
3.088
02222AER/
ISC3
0.721
0.495
0.938
0.818
1.154
1.630
3.829
02222AER/
ISC3
1.045
1.149
1.608
1.550
2.414
2.494
2.526
02222AER/
ISC3
1.025
1.050
1.356
1.544
2.132
2.182
2.265
02222AER/
99351AER
0.908
0.932
0.900
0.889
0.939
0.963
0.976
02222AER/
99351AER
0.863
0.850
0.924
0.923
0.944
0.894
0.984
02222AER/
99351AER
0.940
0.915
0.845
0.760
0.766
0.731
0.744
02222AER/
99351AER
0.986
0.967
0.993
0.912
0.996
0.979
0.990
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
70
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
R200TO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R200TP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R10VOLFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R10VOLFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
3.441 E+01
2.226E+01
1.723E+01
1.446E+01
5.957E+00
3.802E+00
5.140E-01
ISC3
3.479E+01
3.130E+01
1.512E+01
1.299E+01
4.775E+00
4.005E+00
3.440E-01
ISC3
6.407E+04
4.611E+04
3.675E+04
3.094E+04
1.342E+04
1.102E+04
2.496E+03
ISC3
8.044E+04
8.004E+04
4.150E+04
3.422E+04
1.719E+04
1.191E+04
1.656E+03
99351AER/
ISC3
1.004
0.910
0.923
0.746
0.626
0.931
0.930
99351AER/
ISC3
0.830
0.577
0.755
0.774
0.852
0.812
1.073
99351AER/
ISC3
0.909
1.249
1.154
1.296
1.142
1.150
1.059
99351AER/
ISC3
0.900
0.768
1.276
1.168
1.070
1.025
1.026
02222AER/
ISC3
0.918
0.888
0.831
0.677
0.549
0.828
0.860
02222AER/
ISC3
0.720
0.495
0.705
0.723
0.811
0.728
1.058
02222AER/
ISC3
0.909
1.249
1.154
1.206
1.054
1.109
1.054
02222AER/
ISC3
0.900
0.768
1.276
1.168
1.063
1.010
1.039
02222AER/
99351AER
0.915
0.976
0.900
0.907
0.878
0.890
0.925
02222AER/
99351AER
0.867
0.859
0.934
0.933
0.952
0.897
0.986
02222AER/
99351AER
1.000
1.000
1.000
0.931
0.923
0.964
0.995
02222AER/
99351AER
1.000
1.000
1.000
1.000
0.994
0.986
1.012
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
71
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
R35VOLFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
R35VOLFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
RAREFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
RAREFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
1.347E+04
8.979E+03
6.060E+03
4.795E+03
2.022E+03
1.728E+03
4.123E+02
ISC3
1.457E+04
1.024E+04
6.079E+03
5.010E+03
2.178E+03
1.807E+03
2.988E+02
ISC3
1.374E+04
1.374E+04
1.317E+04
1.218E+04
6.654E+03
5.904E+03
2.573E+03
ISC3
2.047E+04
1.983E+04
1.532E+04
1.257E+04
7.766E+03
7.353E+03
3.044E+03
99351AER/
ISC3
0.683
0.962
0.906
0.932
0.890
0.889
0.925
99351AER/
ISC3
0.905
0.999
1.026
0.973
0.810
0.967
0.915
99351AER/
ISC3
2.040
1.382
1.379
1.201
1.169
0.995
0.646
99351AER/
ISC3
1.509
1.515
1.280
1.324
1.057
1.050
0.715
02222AER/
ISC3
0.619
0.875
0.807
0.880
0.897
0.840
0.920
02222AER/
ISC3
0.818
0.847
0.956
0.868
0.807
0.930
0.913
02222AER/
ISC3
1.954
1.312
1.305
1.132
1.019
0.832
0.614
02222AER/
ISC3
1.441
1.441
1.252
1.292
1.010
0.989
0.682
02222AER/
99351AER
0.906
0.910
0.891
0.945
1.008
0.945
0.994
02222AER/
99351AER
0.904
0.848
0.932
0.892
0.996
0.961
0.998
02222AER/
99351AER
0.958
0.950
0.946
0.943
0.872
0.836
0.950
02222AER/
99351AER
0.955
0.951
0.978
0.975
0.955
0.942
0.954
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
72
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
U05NDNBO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U05NDNBP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U10NDNBO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U10NDNBP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
1.668E+05
1.668E+05
1.284E+05
9.909E+04
3.038E+04
2.785E+04
5.129E+03
ISC3
2.498E+05
1.668E+05
1.382E+05
1.106E+05
5.385E+04
2.891 E+04
3.033E+03
ISC3
1.588E+05
1.588E+05
1.223E+05
9.443E+04
2.899E+04
2.661 E+04
4.942E+03
ISC3
2.375E+05
1.588E+05
1.315E+05
1.053E+05
5.135E+04
2.774E+04
2.923E+03
99351AER/
ISC3
2.096
2.078
1.869
2.130
2.103
1.818
0.992
99351AER/
ISC3
2.743
3.152
2.318
1.841
1.537
1.502
1.260
99351AER/
ISC3
1.127
1.125
1.061
1.322
1.497
1.163
0.941
99351AER/
ISC3
1.255
1.696
1.319
1.136
0.949
1.344
1.153
02222AER/
ISC3
0.887
0.852
0.804
0.813
1.091
1.041
1.261
02222AER/
ISC3
0.592
0.873
0.857
0.849
0.801
1.013
1.412
02222AER/
ISC3
0.533
0.516
0.523
0.634
0.864
0.860
1.187
02222AER/
ISC3
0.356
0.525
0.575
0.598
0.570
0.809
1.342
02222AER/
99351AER
0.423
0.410
0.430
0.382
0.519
0.573
1.271
02222AER/
99351AER
0.216
0.277
0.370
0.461
0.521
0.674
1.120
02222AER/
99351AER
0.473
0.459
0.493
0.479
0.577
0.739
1.262
02222AER/
99351AER
0.284
0.310
0.436
0.526
0.601
0.602
1.164
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
73
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
U20NDNBO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U20NDNBP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U35MFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U35MFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
5.789E+04
5.078E+04
3.907E+04
3.145E+04
1.145E+04
9.885E+03
2.119E+03
ISC3
7.568E+04
5.516E+04
4.189E+04
3.361 E+04
1.730E+04
1.089E+04
1.398E+03
ISC3
2.222E+03
1.859E+03
1.462E+03
1.403E+03
8.936E+02
8.090E+02
1.415E+02
ISC3
2.358E+03
1.859E+03
1.644E+03
1.401E+03
9.331 E+02
7.561 E+02
1.037E+02
99351AER/
ISC3
0.522
0.422
0.485
0.432
0.658
0.713
1.013
99351AER/
ISC3
0.365
0.482
0.443
0.462
0.468
0.682
0.997
99351AER/
ISC3
0.691
0.690
0.692
0.683
0.595
0.644
0.795
99351AER/
ISC3
0.694
0.820
0.644
0.604
0.466
0.477
0.611
02222AER/
ISC3
0.582
0.588
0.384
0.431
0.511
0.544
0.670
02222AER/
ISC3
0.438
0.535
0.528
0.500
0.346
0.469
0.799
02222AER/
ISC3
0.567
0.638
0.567
0.558
0.456
0.441
0.401
02222AER/
ISC3
0.833
0.676
0.574
0.516
0.272
0.303
0.399
02222AER/
99351AER
1.116
1.392
0.792
0.996
0.777
0.763
0.662
02222AER/
99351AER
1.200
1.110
1.192
1.081
0.739
0.687
0.801
02222AER/
99351AER
0.820
0.925
0.820
0.818
0.766
0.684
0.504
02222AER/
99351AER
1.201
0.824
0.891
0.854
0.583
0.635
0.653
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
74
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
U35BFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U35BFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U100FO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U100FP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
6.987E+02
5.931 E+02
4.513E+02
3.648E+02
2.849E+02
2.716E+02
3.748E+01
ISC3
5.718E+02
4.429E+02
3.615E+02
3.473E+02
2.1 71 E+02
1.927E+02
2.568E+01
ISC3
8.344E+01
7.354E+01
5.392E+01
4.886E+01
3.015E+01
2.984E+01
4.082E+00
ISC3
8.015E+01
7.214E+01
5.665E+01
4.963E+01
2.329E+01
2.022E+01
2.602E+00
99351AER/
ISC3
0.686
0.754
0.925
1.111
1.027
0.997
0.975
99351AER/
ISC3
0.787
0.990
1.128
1.094
1.046
1.066
1.027
99351AER/
ISC3
0.644
0.709
0.912
0.953
0.601
0.519
0.549
99351AER/
ISC3
0.664
0.703
0.812
0.820
0.736
0.670
0.648
02222AER/
ISC3
0.539
0.621
0.724
0.841
0.548
0.477
0.580
02222AER/
ISC3
0.615
0.773
0.866
0.894
0.593
0.614
0.649
02222AER/
ISC3
0.601
0.591
0.722
0.737
0.383
0.367
0.392
02222AER/
ISC3
0.571
0.607
0.636
0.634
0.555
0.494
0.479
02222AER/
99351AER
0.786
0.823
0.782
0.758
0.533
0.479
0.594
02222AER/
99351AER
0.782
0.781
0.768
0.817
0.567
0.576
0.631
02222AER/
99351AER
0.934
0.833
0.792
0.773
0.638
0.707
0.714
02222AER/
99351AER
0.859
0.864
0.783
0.773
0.754
0.738
0.739
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
75
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
U200FO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U200FP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U35TO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U35TP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
3.134E+01
2.972E+01
2.152E+01
1.978E+01
1.107E+01
9.360E+00
1.276E+00
ISC3
3.104E+01
2.726E+01
2.028E+01
1.941E+01
8.419E+00
6.496E+00
8.800E-01
ISC3
4.808E+02
4.364E+02
3.433E+02
2.541 E+02
1.271E+02
1.107E+02
1.826E+01
ISC3
6.314E+02
4.922E+02
3.071 E+02
2.784E+02
1.516E+02
1.333E+02
2.224E+01
99351AER/
ISC3
0.952
0.614
0.651
0.562
0.382
0.449
0.490
99351AER/
ISC3
0.804
0.570
0.550
0.559
0.524
0.537
0.527
99351AER/
ISC3
0.556
0.604
0.749
0.994
1.295
1.467
1.520
99351AER/
ISC3
0.420
0.522
0.805
0.884
1.053
0.961
0.762
02222AER/
ISC3
1.033
0.643
0.760
0.576
0.314
0.350
0.378
02222AER/
ISC3
0.935
0.920
0.644
0.550
0.688
0.527
0.435
02222AER/
ISC3
0.465
0.477
0.533
0.705
0.883
0.898
0.759
02222AER/
ISC3
0.367
0.461
0.698
0.731
0.664
0.749
0.554
02222AER/
99351AER
1.085
1.048
1.167
1.025
0.822
0.779
0.771
02222AER/
99351AER
1.163
1.613
1.171
0.984
1.312
0.981
0.825
02222AER/
99351AER
0.838
0.790
0.711
0.710
0.682
0.612
0.499
02222AER/
99351AER
0.875
0.884
0.866
0.826
0.631
0.780
0.728
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
76
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
U200TO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U200TP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U10VOLFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U10VOLFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
7.411E+01
6.340E+01
5.143E+01
4.184E+01
1.332E+01
1.160E+01
1.855E+00
ISC3
7.576E+01
7.495E+01
4.611E+01
4.378E+01
1.884E+01
1.631E+01
1.673E+00
ISC3
2.722E+04
2.722E+04
2.225E+04
2.007E+04
8.807E+03
7.552E+03
1.775E+03
ISC3
4.076E+04
3.631 E+04
2.595E+04
2.219E+04
1.102E+04
7.792E+03
1.106E+03
99351AER/
ISC3
0.385
0.320
0.260
0.267
0.328
0.369
0.343
99351AER/
ISC3
0.323
0.279
0.275
0.264
0.238
0.218
0.304
99351AER/
ISC3
1.140
1.132
1.104
1.189
1.261
1.159
1.319
99351AER/
ISC3
1.070
1.114
1.148
1.062
1.043
1.108
1.388
02222AER/
ISC3
0.426
0.312
0.326
0.282
0.262
0.296
0.277
02222AER/
ISC3
0.389
0.334
0.266
0.244
0.330
0.203
0.231
02222AER/
ISC3
1.040
1.027
1.007
1.070
1.146
1.151
1.348
02222AER/
ISC3
0.850
0.861
1.031
0.990
0.974
1.109
1.492
02222AER/
99351AER
1.106
0.974
1.253
1.055
0.798
0.803
0.807
02222AER/
99351AER
1.205
1.195
0.966
0.925
1.384
0.933
0.760
02222AER/
99351AER
0.913
0.908
0.912
0.900
0.909
0.993
1.022
02222AER/
99351AER
0.794
0.773
0.898
0.932
0.934
1.001
1.075
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
77
-------
Appendix D. Results of the flat and simple terrain analysis. The ISC3
concentrations are in ug/m3 and the last 3 columns are concentration ratios.
U35VOLFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
U35VOLFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
UAREFO
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
UAREFP
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
1.079E+04
8.430E+03
5.600E+03
5.198E+03
2.736E+03
2.149E+03
5.942E+02
ISC3
1.079E+04
9.609E+03
6.187E+03
5.280E+03
2.839E+03
2.302E+03
4.048E+02
ISC3
4.902E+03
4.902E+03
4.787E+03
4.411E+03
2.651 E+03
2.276E+03
1.095E+03
ISC3
7.322E+03
7.202E+03
5.631 E+03
4.691 E+03
3.005E+03
2.882E+03
1.287E+03
99351AER/
ISC3
0.768
0.919
0.890
0.783
0.594
0.681
0.653
99351AER/
ISC3
1.114
0.981
0.939
0.868
0.554
0.634
0.680
99351AER/
ISC3
4.254
2.856
2.820
2.405
2.168
1.823
1.151
99351AER/
ISC3
3.157
3.150
2.576
2.668
1.893
1.954
1.272
02222AER/
ISC3
0.773
0.932
0.873
0.790
0.593
0.639
0.593
02222AER/
ISC3
1.105
0.903
0.940
0.824
0.533
0.610
0.650
02222AER/
ISC3
1.383
1.247
1.224
1.246
1.281
1.373
1.434
02222AER/
ISC3
0.958
0.932
1.015
1.178
1.201
1.237
1.417
02222AER/
99351AER
1.007
1.014
0.980
1.009
0.998
0.938
0.909
02222AER/
99351AER
0.992
0.921
1.000
0.949
0.962
0.963
0.955
02222AER/
99351AER
0.325
0.437
0.434
0.518
0.591
0.753
1.246
02222AER/
99351AER
0.303
0.296
0.394
0.441
0.635
0.633
1.114
The first letter indicates urban (U) or rural (R) settings: the number indicates the stack height (meters): the next set of
letters - VOL, volume source; ARE, area source; ND, no downwash; NB, no building; M, moderately buoyant; B,
bouyant plume; F, flat terrain; T, simple terrain: the last letter indicates the met data site - O, Oklahoma City; P,
Pittsburgh
78
-------
APPENDIX E
COMPLEX TERRAIN MODELING RESULTS:
LISTING OF REGULATORY DESIGN CONCENTRATIONS (UG/M3)
79
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3 and the last 3
columns are concentration ratios.
PHLLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MCLLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MALLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
CCLLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
88.349
87.987
78.591
73.306
24.103
18.047
2.703
ISC3
51.612
50.919
48.584
41.564
12.846
10.534
1.348
ISC3
43.626
43.351
37.516
34.43
9.473
8.015
0.564
ISC3
48.416
48.416
42.68
32.291
9.707
7.256
0.48
02222AER/
ISC3
0.39
0.32
0.20
0.19
0.18
0.20
0.19
02222AER/
ISC3
0.51
0.41
0.21
0.24
0.16
0.17
0.17
02222AER/
ISC3
0.26
0.25
0.11
0.10
0.11
0.12
0.16
02222AER/
ISC3
0.30
0.24
0.20
0.19
0.17
0.16
0.20
02222AER/
CTDM+
0.67
0.55
0.54
0.48
0.38
0.44
0.41
02222AER/
CTDM+
1.04
0.97
0.63
1.08
0.53
0.63
0.52
02222AER/
CTDM+
0.41
0.56
0.47
0.44
0.79
0.74
0.62
02222AER/
CTDM+
1.23
1.22
1.77
1.78
2.06
1.57
1.18
02222AER/
99351 AER
0.87
0.74
0.61
0.61
0.75
0.89
0.89
02222AER/
99351 AER
0.85
0.96
0.87
0.93
0.91
1.01
1.03
02222AER/
99351 AER
0.91
0.91
0.92
0.91
0.99
0.99
1.09
02222AER/
99351 AER
1.00
1.00
1.01
1.05
0.99
1.02
1.18
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 8 0
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3 and the last 3
columns are concentration ratios.
PHLLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MCLLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MALLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24 Hour H2H
Annual
CCLLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
8.293
7.971
4.908
3.841
1.122
0.739
0.067
ISC3
8.024
7.649
5.108
4.486
1.133
0.979
0.109
ISC3
7.78
7.662
4.03
3.327
0.842
0.57
0.038
ISC3
8.073
7.663
4.604
3.016
0.805
0.762
0.037
02222AER/
ISC3
0.40
0.33
0.25
0.27
0.18
0.26
0.27
02222AER/
ISC3
0.47
0.37
0.26
0.24
0.32
0.32
0.33
02222AER/
ISC3
0.19
0.14
0.17
0.17
0.20
0.20
0.21
02222AER/
ISC3
0.22
0.21
0.22
0.22
0.17
0.12
0.24
02222AER/
CTDM+
1.17
1.13
0.87
0.84
0.80
0.96
1.20
02222AER/
CTDM+
1.23
1.19
0.73
0.84
1.00
0.88
0.88
02222AER/
CTDM+
0.74
0.59
1.02
0.92
1.61
1.33
0.89
02222AER/
CTDM+
1.22
1.40
1.50
1.68
1.30
1.07
1.13
02222AER/
99351 AER
0.94
0.81
0.76
0.90
0.80
0.91
1.00
02222AER/
99351 AER
0.90
0.92
0.90
0.95
1.01
0.98
1.01
02222AER/
99351 AER
0.99
1.02
1.00
1.00
1.00
1.01
1.19
02222AER/
99351 AER
1.00
1.10
1.00
1.01
1.01
1.12
1.36
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 81
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3 and the last 3
columns are concentration ratios.
PHLHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MCLHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MALHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
CCLHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
18.709
18.672
17.274
16.654
5.399
4.246
0.581
ISC3
9.41
9.385
9.208
9.164
3.195
2.775
0.249
ISC3
5.684
5.684
5.534
4.72
1.284
0.836
0.052
ISC3
0.878
0.869
0.788
0.779
0.304
0.143
0.01
02222AER/
ISC3
0.31
0.27
0.20
0.17
0.13
0.15
0.11
02222AER/
ISC3
0.38
0.28
0.23
0.20
0.12
0.13
0.10
02222AER/
ISC3
0.22
0.19
0.10
0.11
0.08
0.09
0.13
02222AER/
ISC3
0.38
0.32
0.15
0.13
0.09
0.18
0.20
02222AER/
CTDM+
0.66
0.66
0.77
0.75
0.70
0.80
0.97
02222AER/
CTDM+
0.55
0.58
0.97
1.10
0.89
0.95
0.75
02222AER/
CTDM+
0.34
0.30
0.23
0.39
0.31
0.28
0.39
02222AER/
CTDM+
0.22
0.22
0.14
0.18
0.18
0.34
0.67
02222AER/
99351 AER
1.01
1.01
1.00
1.00
1.00
1.01
1.03
02222AER/
99351 AER
1.20
1.02
1.01
1.01
1.02
1.02
1.05
02222AER/
99351 AER
0.97
1.00
1.00
1.01
0.98
0.98
1.00
02222AER/
99351 AER
0.71
0.85
0.76
0.95
0.87
1.29
1.60
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 8 2
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3 and the last 3
columns are concentration ratios.
PHLHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24 Hour H2H
Annual
MCLHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MALHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
CCLHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
2.309
2.309
2.037
1.867
0.445
0.36
0.026
ISC3
1.547
1.547
1.477
1.164
0.408
0.284
0.028
ISC3
1.381
1.381
1.321
0.908
0.307
0.207
0.012
ISC3
0.27
0.262
0.219
0.217
0.088
0.044
0.003
02222AER/
ISC3
0.35
0.27
0.16
0.16
0.16
0.14
0.12
02222AER/
ISC3
0.54
0.29
0.20
0.19
0.12
0.12
0.14
02222AER/
ISC3
0.22
0.17
0.08
0.11
0.07
0.10
0.25
02222AER/
ISC3
0.79
0.73
0.41
0.37
0.16
0.27
0.33
02222AER/
CTDM+
0.45
0.39
0.51
0.57
0.52
0.63
0.75
02222AER/
CTDM+
0.60
0.52
0.66
0.59
0.78
0.62
0.80
02222AER/
CTDM+
0.31
0.34
0.31
0.34
0.42
0.40
0.75
02222AER/
CTDM+
0.35
0.47
0.39
0.41
0.45
0.48
1.00
02222AER/
99351 AER
1.23
1.09
1.01
1.39
1.05
1.22
1.17
02222AER/
99351 AER
1.80
1.18
1.12
1.23
1.07
1.01
1.12
02222AER/
99351 AER
1.00
0.91
0.84
1.01
0.84
0.90
1.20
02222AER/
99351 AER
0.86
1.00
0.97
0.95
0.85
0.97
1.46
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 8 3
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3 and the last 3
columns are concentration ratios.
PHHLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MCHLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MAHLC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
PHHLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
49.86
49.715
28.962
26.97
9.578
8.275
1.022
ISC3
28.886
28.812
19.196
16.396
4.287
3.845
0.579
ISC3
15.289
15.289
8.119
6.722
2.004
1.815
0.128
ISC3
7.064
6.271
2.727
2.338
0.64
0.44
0.037
02222AER/
ISC3
0.35
0.26
0.31
0.28
0.30
0.27
0.25
02222AER/
ISC3
0.41
0.36
0.32
0.33
0.33
0.31
0.17
02222AER/
ISC3
0.43
0.28
0.36
0.28
0.25
0.16
0.19
02222AER/
ISC3
0.33
0.33
0.32
0.30
0.20
0.27
0.19
02222AER/
CTDM+
0.90
0.79
0.96
1.03
0.94
1.08
0.82
02222AER/
CTDM+
0.86
2.13
1.33
1.76
1.63
1.49
0.92
02222AER/
CTDM+
0.67
0.78
0.74
0.88
1.02
0.71
0.71
02222AER/
CTDM+
0.80
0.82
0.85
0.78
0.78
0.90
0.88
02222AER/
99351 AER
1.00
1.00
1.00
1.00
1.00
1.00
1.01
02222AER/
99351 AER
1.00
1.00
1.00
1.00
1.01
1.00
1.01
02222AER/
99351 AER
1.00
1.00
1.00
1.00
1.00
1.00
1.01
02222AER/
99351 AER
1.00
1.00
1.00
1.00
1.01
1.00
1.18
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 8 4
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3 and the last 3
columns are concentration ratios.
MCHLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MAHLF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
PHHHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MCHHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
6.74
6.254
4.232
2.611
0.61
0.566
0.058
ISC3
6.509
6.371
2.17
2.16
0.43
0.423
0.022
ISC3
8.606
8.578
6.329
6.16
2.065
1.635
0.205
ISC3
1.029
1.026
0.945
0.935
0.389
0.371
0.022
02222AER/
ISC3
0.26
0.28
0.18
0.22
0.19
0.16
0.12
02222AER/
ISC3
0.22
0.14
0.22
0.19
0.17
0.14
0.27
02222AER/
ISC3
0.23
0.14
0.11
0.08
0.18
0.09
0.10
02222AER/
ISC3
0.66
0.28
0.24
0.15
0.17
0.11
0.18
02222AER/
CTDM+
0.85
1.58
1.09
1.39
1.30
1.39
1.00
02222AER/
CTDM+
0.81
0.82
0.67
0.92
0.83
0.72
0.86
02222AER/
CTDM+
0.32
0.29
0.31
0.27
0.91
0.43
1.25
02222AER/
CTDM+
0.40
0.25
0.31
0.25
0.60
0.44
0.50
02222AER/
99351 AER
1.00
1.00
1.08
1.00
1.00
1.23
1.00
02222AER/
99351 AER
1.00
1.00
1.00
1.00
1.00
0.99
1.10
02222AER/
99351 AER
1.25
1.00
1.07
0.99
1.00
1.00
0.99
02222AER/
99351 AER
0.95
0.91
0.95
0.98
1.00
0.95
1.02
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 8 5
-------
Appendix E. Complex terrain results. The ISC3 concentrations are in ug/m3
and the last 3 columns are concentration ratios.
MAHHC
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
PHHHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24 Hour H2H
Annual
MCHHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
MAHHF
1 HourHIH
1 HourH2H
3 HourHIH
3HourH2H
24 HourHIH
24HourH2H
Annual
ISC3
0.659
0.643
0.614
0.525
0.124
0.077
0.006
ISC3
1.625
1.625
1.083
0.964
0.204
0.16
0.011
ISC3
0.274
0.272
0.235
0.233
0.095
0.053
0.007
ISC3
0.276
0.266
0.217
0.193
0.053
0.034
0.003
02222AER/
ISC3
0.38
0.32
0.19
0.16
0.27
0.38
0.33
02222AER/
ISC3
0.27
0.11
0.14
0.08
0.11
0.12
0.09
02222AER/
ISC3
0.59
0.51
0.33
0.30
0.21
0.25
0.29
02222AER/
ISC3
0.42
0.42
0.29
0.24
0.23
0.35
0.33
02222AER/
CTDM+
0.20
0.23
0.27
0.24
0.28
0.35
0.40
02222AER/
CTDM+
0.33
0.16
0.23
0.21
0.24
0.23
0.50
02222AER/
CTDM+
0.56
0.71
0.63
0.85
1.11
0.72
1.00
02222AER/
CTDM+
0.69
0.86
0.78
0.73
0.48
0.67
0.50
02222AER/
99351 AER
1.00
0.93
0.94
0.93
0.97
0.96
0.97
02222AER/
99351 AER
2.66
1.31
1.71
0.98
1.50
1.56
0.99
02222AER/
99351 AER
0.93
0.82
0.94
0.96
1.01
1.02
1.22
02222AER/
99351 AER
0.75
0.88
0.74
0.85
0.85
1.00
0.66
The code for each scenario evaluated is as follows: The first 2 letters refer to the name of the hill: PH = Piedmont,
MC = Montour Crosswind, MA = Montour Alongwind, CC = Cinder Cone Butte. The 3rd letter refers to the stack
height: L = 30 meters, H = 150m. The fourth letter refers to the buoyancy: L = low, H = high. The fifth letter stands
for the distance between the source and the hill: C = close or 1 kilometer, F = far or 10 km. 8 6
-------
TECHNICAL REPORT DATA
(Please read Instructions on reverse before completing)
1. REPORT NO.
EPA-454/R-03-002
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Comparison of Regulatory Design Concentrations: AERMOD
vs. ISCST3, CTDMPLUS, ISC-PRIME
5. REORT DATE
June 2003
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
See below.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emissions Monitoring and Analysis Division
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final technical report.
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT This report is a consequence analysis for the implementation of a new air dispersion model. A consequence
analysis is designed to give the user community a sense of how regulatory design concentrations from the new model compare to
those from an established model via a series of "representative" examples. For this study, the new model is AERMOD with the
PRIME algorithms. The existing regulatory models used in this report are ISCST3, ISC-PRIME, and CTDMPLUS. This analysis
shows, for an extensive number of typical source scenarios, the effects of the new model as compared to the existing regulatory
model which it replaces. Overall, except for complex terrain, the models produce rather similar results, although there are
significant differences for individual source types and settings. As expected in complex terrain, AERMOD typically produces
concentrations that are lower than ISCST3. The model evaluation results, where available, support the differences seen between
the models.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
consequence analysis, regulatory design concentrations,
AERMOD, ISCST3, CTDMPLUS, PRIM E,ISC-PRIM
Air Pollution models
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (Report) Unclassified
21. No of pages 91
20. SECURITY CLASS (Page) Unclassified
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION IS OBSOLETE
-------
United States Office of Air Quality Planning and Standards Publication No. EPA-454/R-03-002
Environmental Protection Emissions Monitoring and Analysis Division June 2003
Agency Research Triangle Park, NC
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